I would probably have checked the river and called a small-medium bet like you were planning. Unimproved AA on the river isnt anything to get another stack allin.

It looked like he was playing for that pair after the turn because I dont see any possible straight draw for him to be drawing too. He may have called another river bet of 12 or something, but its hard telling.

I think you did with AA just what is supposed to be done. You played it aggressively and won a pretty decent pot without much difficulty.