Fold top pair nines to TAG's turn raise? Prty 20/40

[Benjamin]

Party Poker 20/40 Hold'em (9 handed) FTR converter on zerodivide.cx

Preflop: Hero is BB with 9 [img]/images/graemlins/club.gif[/img], A [img]/images/graemlins/diamond.gif[/img].
2 folds, MP1 calls, 4 folds, SB completes, Hero checks.

- MP1 is tight and not terribly aggressive preflop at 17/6 and with pretty high aggression postflop. I don't know him real well, but he looks like a winner in the full ring from what I've seen. SB is terrible loose passive 66/6.

Flop: (3 SB) 2 [img]/images/graemlins/heart.gif[/img], 5 [img]/images/graemlins/club.gif[/img], 9 [img]/images/graemlins/heart.gif[/img] (3 players)
SB checks, Hero bets, MP1 raises, SB calls, Hero 3-bets, MP1 calls, SB calls.

Turn: (6 BB) 8 [img]/images/graemlins/diamond.gif[/img] (3 players)
SB checks, Hero bets, MP1 raises, SB folds, Hero????

Comments on any street welcome, but I'm most interested in the turn.

B.