Wait or go (and why)?

[Octopus]

Third orbit at the table. BB is 33/10, so far. No idea of his 3-bet standards. I have seen him raise the flop with 55 on a 972 board and then take a free card on the turn. SB seems reasonable; he has been running good. CO is bad - loose and passive.

Party Poker (8 handed) converter

Preflop: Hero is MP1 with 9[img]/images/graemlins/club.gif[/img], 9[img]/images/graemlins/spade.gif[/img].
2 folds, Hero raises, 1 fold, CO calls, 1 fold, SB calls, BB 3-bets, all call.

Flop: 7[img]/images/graemlins/heart.gif[/img], 5[img]/images/graemlins/club.gif[/img], 3[img]/images/graemlins/heart.gif[/img] <font color="#0000FF">(4 players - 12 SB)</font>
SB checks, BB bets, Hero ???

Is this a possible wait-for-the-turn, or a clear raise-now? One the one hand, there are plently of possible 4-6 outers I would love to see fold. On the other hand, the 4 outers probably didn't make it this far and the 6 outers won't fold anyway at this point (but might fold on the turn). On the third hand, there are a huge number of cards which I would hate to see (hearts and aces topping that list). Finally there is a fairly good chance I am behind here, but I am not sure if I can better find out with a raise here or on the turn.

Thoughts?