If the villian is a weak player I'd have him on an Ace with a duff kicker, at best (well not as high as yours) It seems to suit his betting pattern as he's just flat calling pre-flop & flop, then raising once the Ace comes out.
I wouldn't put him on a 9, as his $1.95 bet isn't because he's scared of a flush, otherwise he should have re-raised on the flop, as there's a good chance you would call, if you were fishing. If he had full house, surely he'd give you better pot odds
if he bet on the turn.
7 is a possibility if he usually plays rags pre-flop, but he may be trying to make you think he has the Ace.
Flush draw is quite likely & he was actually semi-bluffing (but surely he'd put a value bet in on the flop?)
Having said all this, I still put him on the Ace, so I'd raise half the pot on the river and leave the rest to him. If he re-raises a call would be best, if he folds he most likely had a flush draw, if he flat calls he's got a lower 2 pair than you (or at least kicker)