Upvote:1
A few more interpretations:
A Molinist might say that God prepares all people by placing them in circumstances in which He knew their free choices would lead them to be saved, ie glory, and that this is a general statement rather than a reference to specific people in the past
Some would say that this verse refers to the transition from the old covenant to the new one; the vessels of destruction in v. 22 would then be the Israelites who rebelled against him constantly in the desert, ie those He endured with much patience, who He then took the promise from and gave to those He had prepared through the Prophets and the teachings of Christ himself. This general idea of the covenant transferring (excuse my imprecise terminology) from the Jews to all nations is common among non-Reformed takes on Romans 9
It could be referring to all those who will be saved prepared simply by virtue of the fact that God's plan includes their being saved and has done from eternity past
As a non-Reformed, these are possible ways I might interpret it, I lean towards the first and second one