A9...oh goodness...help my aggressiveness

I'm trying to play a slightly more aggressive game, and I'm trying to figure out how to do it correctly. Any suggestions on this hand?
Should I had just folded this hand pre-flop since I have about 56BB?
What about calling the re-raise?
What if I had pushed at his river check...any good?

My only note was that he's been sLAG since the tourney started.

Full Tilt Poker
No Limit Holdem Tournament
Blinds: t20/t40
8 players

Stack sizes:
UTG: t1400
UTG+1: t2580
MP1: t1235
MP2: t225
Im_new: t2550
Button: t920
SB: t1995
BB: t2595

Pre-flop: (8 players) Im_new is CO with A :club: 9 :spade:
4 folds, Im_new raises to t120, 2 folds, BB calls t80 (pot was t180).

Flop: 5 :spade: 4 :diamond: A :heart: (t260, 2 players)
BB checks, Im_new bets t180, BB calls t180 (pot was t440).

Turn: K :club: (t620, 2 players)
BB checks, Im_new bets t400, BB raises to t800, Im_new calls t400 (pot was t1820).

River: 8 :spade: (t2220, 2 players)
BB checks, Im_new checks.

Results:
Final pot: t2220

With TPWK I would check behind on the turn to keep the pot small. What do you think he is calling a pf raise with (which btw should be 90) then c/c flop and c/r the turn? My best guess would say Ax (where x can be anything- some people even play AK like this), 67 (very unlikely) or a set.

Most of the time you are behind, so the check behind on the river is good imo.

Overall, seems from BB's play that he thinks you are stealing and c-betting. Or has a monster...

Pre-flop, standard steal situation and your hand is good enough for that - although I would often fold here this early on, the blinds aren't really worth stealing yet. Play super-tight early and get LAG later...

Flop. I like it, but am scared by the BB check-call - from here on in I want to see the river cheaply.

Turn. Dunno, calling is fine, raising is maybe - I don't think I fold here.

River, I like that you checked behind. I wouldn't be that surprised to see KTen here, but AJ and other hands that beat you are likely enough too.

Welcome to FTR, it's good to have you here. BTW if you are playing SNGs, you can also post hands in the SNG Tourney Tactics forum, there are a lot of fellow SNG players who visit that forum.

On your hand, I agree with Zee, check behind on the turn. There are not that many draws to really worry about so you don't need to "defend" your hand from them.

Thanks guys..I'm headed to the SNG forum to pick some brains. I have a feeling I'll be staying around this site.