I posted a similiar question just after yours... I'm fairly confident the right call here is to check. In Theory of Poker, Sklansky argues that you should not bet once the cards are out if you cannot beat the holding of a probable caller. Out of the possible card combinations he could be playing 9's up (probably 9's and 3's), Aces-up, trips, or even a full house. Given his loose preflop play any of those are about as likely. If you raise, 9's up will mostly fold, Aces-up, trips, or full house will all call and possibly check-raise. The only calling hand you can beat is A with a 10, 8, 7, 6, 5, 4 or 2.

Betting here will cause most hands you've beaten to fold. Few hands will call that you can beat. Given your (rightly played) aggressive betting it's just as likely he's holding trips or better and is going for a check-call or check-raise... I would check and see the showdown.

- Hungry J0e