OOP Against a LAG, checkraise semibluff?

[Chicago Twister]

He's playing aggressive, although I'm not sure yet if hes a lagtard or just a lag. Plus he has position on me. Every time he didnt fold when I raise preflop, he has 3bet me.

Full Tilt Poker - No Limit Hold'em Cash Game - $0.25/$0.50 Blinds - 6 Players - (LegoPoker Hand History Converter)

SB: $59.95
BB: $53.75
UTG: $79.30
MP: $17.30
Hero (CO): $55.60
BTN: $45.45

Preflop: Hero is dealt 9[img]/images/graemlins/spade.gif[/img] K[img]/images/graemlins/spade.gif[/img] (6 Players)
2 folds, <font color="red">Hero raises to $2.00</font>, <font color="red">BTN raises to $7.20</font>, 2 folds, Hero calls $5.20

Flop: ($15.15) 7[img]/images/graemlins/spade.gif[/img] 5[img]/images/graemlins/heart.gif[/img] T[img]/images/graemlins/spade.gif[/img] (2 Players)
Hero checks, <font color="red">BTN bets $11.70</font>, <font color="red">Hero raises all-in to $48.40</font>