Overstayed my VWP in 2008 due to marriage – will I be denied a B2?

You are not eligible for ESTA because you did overstay, there’s no ambiguity about that. I see no need to call CBP, they are not there to help you and many times you will get wrong information anyway. The only course open is to apply for a visa. If you apply for ESTA you could get approved, but you will certainly be denied entry at the airport and deported expeditiously back to Italy. You do not have a bar to entry because per your timeline, your overstay was less than 180 days

If you repeat what you wrote here to the consular officer, your case can be problematic and you could be banned from ever entering the USA because of the presumption of immigrant intent, immigration fraud and based on your own statement here. You stated:

At that point I was ready to file my application for residency as a
spouse of an American citizen.

Do not under any circumstances mention that to the consular officer at the interview. Why? Under the old 30/60 rule, the very fact that you got married shortly after entry AND intended to file for adjustment of status is used to establish immigrant intent. This would mean you committed immigration fraud because there’s a presumption of fraud if a person violates his or her non-immigrant status or engages in conduct inconsistent with that status within 90 days of entry. Basically you came in on a non-immigrant status knowing full well your intent was to adjust status. Preconceived intent.

Keep your story to the consular officer simple at the interview. Yes you went to get married. Filing for adjustment of status was not in your plans at that time, marrying your lover was all that was on your mind after which you would return to Italy and work on moving legally to the USA as a spouse. Marrying under ESTA is not a violation of immigration law, it is the filing for adjustment of status within a short time after entering which violates the spirit of things. The good thing is you never filed paperwork to change status so you actually did not commit the fraud, it is your statement here which gives a presumption that you intended to.

Apply for a visa, and fill out the forms accurately. At your interview you will be questioned and answer truthfully (leaving out the intent to file adjustment of status). You are married and from a western developed high income country and I assume you have other ties to Italy which you can demonstrate. Your circumstances have changed significantly in the last ten years.

All other things being equal, you should get a visa. If my answer is difficult to understand, get a competent immigration attorney.

TL:DR

The now eliminated 30/60 Day Rule was in effect and applicable in 2008 when the OP’s incident happened

USCIS 30/60 Day Rule
As a general rule, a person cannot have preconceived intent to enter the U.S. for a purpose different from that permitted under his/her nonimmigrant visa. The U.S. Department of State created the 30/60 day rule and published it in their Foreign Affairs Manual. USCIS adopted the 30/60 day guidelines and use them to help USCIS officers evaluate the likelihood of visa fraud.

30 Days or Less
If you file your adjustment of status application within 30 days of entering the United States, USCIS officers are trained to presume that you are trying to avoid longer procedures. Specifically, they will assume that you had the “preconceived intent” to adjust status before you even arrived in the U.S. Therefore, they’ll say, you obtained a visa fraudulently to evade the normal screening process abroad for the nonimmigrant visa you really wanted.

It’s not likely that someone would fall in love and get married within 30 days of arriving in the United States. However, it is possible. If you are a rare exception, many immigration attorneys will recommend that you wait to get married and file your adjustment of status application.

31-60 Days
If you file the adjustment of status application more than 30 days but less than 60 days of entering the United States, there continues to be significant risk. There is no presumption that you entered in bad faith, but there’s still a strong suspicion that you entered with preconceived intent. In this scenario, you can counter the USCIS officer’s questions with evidence to show a change of circumstances. But it is generally risky to change status within 60 days of entering the U.S.