Could the Revelation have happened right when Jesus died?

“The Revelation of Jesus Christ, which God gave unto him [the apostle John] to show unto His servants things which must shortly come to pass” (Revelation 1:1).

The visions were given to the apostle John when he was on the island of Patmos towards the end of the first century. The seven churches already existed therefore the fulfilment of the prophecies in Revelation could not have occurred at the death and resurrection of Jesus, because the climax of Revelation is the return of Christ to destroy the enemies of God. He has not yet returned, in great power and glory, accompanied by the heavenly hosts. Most of the visions point ahead to the future, when the Antichrist is finally revealed.

First, judgments fall on the church because apostasy had already encroached into the seven churches. Persecution of the saints started in the first century at the hands of various Roman Emperors (political). This is long before Constantine established Christianity as the state religion. Judgment on the church started long before the beginning of Catholicism and the existence of any pope. The apostle Peter was given that title posthumously, centuries after his death.

Persecution of God’s people is the first prophetic word and has continued since then throughout history and is still on-going.

Just as those first century Christians refused to worship the Emperor, and died rather than renounce their Lord and Saviour, the resurrected and glorified Christ Jesus, so too persecution today falls on those of God’s people who refuse to worship either the state or religious organisations. They refuse to give their allegiance to symbolic beasts, the harlot or the Antichrist. This persecution is on-going and will get worse the closer we get to the second coming of Christ Jesus.

The trumpets in Revelation warn of the wrath to come, which wrath started in the first century and has continued for the last 2,000 years. God’s wrath is being felt by humanity even now –just look at what is happening in the world today. But it is the last trump that heralds the Day of Judgment. That day is still future.

No. The prophecies in the Book of Revelation could not have occurred right when Jesus died. For one thing, the author says:

I... was on the island of Patmos because of the word of God and the testimony of Jesus. On the Lord’s Day I was in the Spirit, and I heard behind me a loud voice like a trumpet, which said: “Write on a scroll what you see and send it to the seven churches:" (1:9-11)

According to Acts, it took years for the Gospel to reach into that part of Empire. Before that, the church was active at first in Jerusalem and then the rest of what we now think of as Israel. It took several decades for churches to be established in the cities of Asia Minor to whom copies of the scroll mentioned above were sent.

Secondly, the author identifies himself as "your brother John, a fellow sufferer for the Lord’s sake" (1:9) and refers to the fact that he was on Patmos "because of the Word of the Lord and the testimony of Jesus." This means he had suffered due to persecution and was there either in exile or as a prisoner. The first persecution of Christians organized by the Roman government was under the emperor Nero in 64 CE after the Great Fire of Rome. Another possibility would be the persecution of Domitian three decades later.

In addition, early mentions of John in the writings of the church fathers indicate the book was written during or shortly after the persecution by Emperor Domitian, and John was on Patmos as an exile:

Irenaeus, from Polycarp, dates the book of Revelation shortly before A.D. 96. Domitian’s predecessor deported “some to the most desolate of the islands” (Suetonius, Titus 8), and Domitian apparently followed that example. Patmos certainly qualifies as desolate. The island is butterfly shaped, some ten miles long and stretching to five miles wide on the upper and lower portions. It is barren, rocky, and steep. Wells are scarce, and until sea-conversion technology water was captured in basins through rainfall... If John was not imprisoned, he would have barely existed, working in the chill or hot seasons. There is no evidence that forced labor was required, for living in bleak isolation was considered punishment enough.

These things considered, the Revelation to John is generally thought to have been written no earlier than the time of Nero Caesar. In any case, it could not have been written until the churches had been established in the seven cities of Asia Minor.

There were, indeed, some things that happened right at the point of Jesus' death, and at his resurrection, which are mentioned in the book of the Revelation. That book was written several decades after Jesus' death and resurrection, but that does not preclude it containing a God-given revelation of unseen events at the time of Jesus' death and resurrection. As the Revelation is full of visions and prophetic signs pointing to things that are not visible here on earth, it's well worth while sorting out what signs were fulfilled at the time you ask about. However, it is very obvious that very many other prophetic sayings, signs and visions given to the aged apostle John were for times beyond his era, into the future, and some things still have to happen.

One example of what you might be looking for is in chapter 12; the sign of a woman appearing in the heavens. She is clothed with the sun; the moon is under her feet; 12 stars are her diadem. She gives birth to a male child in the visible heavens. The child is snatched up to God's throne in heaven before a great red dragon can destroy him. There is nothing literal about all this symbolism. But its application supremely fits the time of the Son of God becoming flesh, and returning to heaven as King, having triumphed over sin, death and the devil. That entailed him dying in the flesh first, and that was when Satan, the dragon, was defeated. The victory was won at the cross, and the resurrection proved it. War broke out in heaven and Satan and his hordes were cast down, confined to earth until the rest of the Revelation would be worked out. As this book puts it:

"When Christ went up, he fell down. When Christ obtained the victory, he was cast into defeat. When Christ occupied the throne of God in heaven every throne on earth tottered, swayed, and crumbled... 'Wherefore he saith, When he ascended up on high,he led captivity captive, and gave gifts unto men. Now that he ascended, what is it but that he also descended first into the lower parts of the earth? He that descended is the same also that ascended up far above all heavens, that he might fill all things.' Ephesians 4:8-10" (The Revelation of Jesus Christ, pp 294-303, John Metcalfe

What else is this but Christ coming down to earth, then returning in triumph back to heaven, when the dragon was cast out of there? That happened at Christ's death and resurrection.

However, the last trump, and the last day have yet to happen. The final hour of God's judgement awaits, the resurrection of the bodies of all who have ever died has not yet happened. There is no way all of those parts of the Revelation happened before the close of the first century A.D. I recommend reading all of that 618 page book to grasp the enormity of the whole vision given to John, circa 90 A.D., including very detailed exposition of that part which did happen at Christ's death and resurrection, in chapter 12.