The trouble is though assuming he is a fairly good player, he may well have folded to a reraise on the flop. That board fits to so many possible holdings,

TJ for straight
3 potential sets of trips for 9s 8s and 7s
even 2 pair for hands like 89s or 78s

These are all possible hands someone could be playing in the way I played and I feel a reraise on the flop may get him to lay it down.

However on the river he may feel, oh well I cant lay down AA to potsized bet and make a reluctant call. This may have been the way to get the most money in this case even if not always correct.