You're exactly right crippler, I was going to take time to point that out. Also, you were holding A9o, and the board before the river was AKQ. Now, not knowing what exactly his play was like before the hand started I can't say with certainty what I would have put him on, but you were voulnerable to several hands. Pocket Aces, Pocket Queens, Pocket Kings, J-10, etc. Lately everyone in their brother has become a "trapping" expert, which generally makes people that use the startegy too much, simply take what they call bad beats, when in all actuality they slow play their strong hands and allow a marginal drawing hand to hit. That is one thing that would have crossed my mind if I were you, possibly playing into this donkey's trap. However when he never came over the top of you on the turn, that would be all but out the window.
I can't say for sure what I would have put him on without knowing all the specifics of the hands such as suit of the board, suit of his hand, position, and style of play. You could have played it differently, but he seems like he would have chased anyway and the outcome may have been the same. If you felt confident your aces were boss, maybe jamming the pot here runs him out, but that's a big risk considering that he could have had 4 decent starting hands that would have knocked your dick in the dirt.
I just read your second post in this thread, which I don't know how I missed...I was right there with you until the preference of unsuited and suited middle connectors over hands like AA, AK, and AQ. That makes no sense. I will take AA or AK all day over suited connectors like 8-9 and 7-8. You made the statement that the connectors are "easy" to get away from and I think therein lies the problem. AK and AQ are easy to get away from as well, you just have to resist being married to your hand strictly on the basis that it has paint in it. You would rather have 8-9 than pocket aces? Any made hand is a favorite to connectors, especially AA, the absolute best starting hand. That statement is silly.