From villain's perspective, b/f this river doesn't come across as exploitable I don't think. Every single draw that you could have been b/c flop with, missed, so as far as he knows you can easily be b/f missed draws here and not AJ.

As for the hand in question, if the turn was a J and he c/bombed you I'd be much more likely to fold. The board is so draw heavy, that I wouldn't expect someone to get tricky here that often on turn by checking strength.

(side note: I know this particular villain very well, and I think he has you here a very high percentage of the time)