[Ssmoimo]

To me that hand just screams AJ. I would put him on exactly that.

Evidence... he doesn't reppop you preflop. AQ, AK, JJ+ (all likely his calling range out of his position giving his is playing very tight) are likely to reraise you preflop. AJ likes to call and look at the flop.

When a vunerable hand like AJ hits top pair, check raise is usually the best play, since slow playing is too dangerous and a continuation bet may look like a bluff on this board.

Finally, with a second draw showing up on the board AJ is going to really want to get you out of the hand. If he has been playing tight (possibly scared) even more so. (Especially if he is up a little bit, this little bit more could make him feel pretty good.) Even if you are being a little aggressive I would think a he would not pick an out of position hand to make a move if he hasn't made any other moves all night.