im expected to bet but shoukd i? $20 buy in

[hamnegger]

PokerStars No-Limit Hold'em Tourney, Big Blind is t30 (9 handed) internettexasholdem.com

UTG (t1335)
UTG+1 (t1340)
MP1 (t2010)
MP2 (t2410)
MP3 (t2670)
CO (t1405)
Button (t1400)
Hero (t2205)
BB (t1585)

Preflop: Hero is SB with 4[img]/images/graemlins/spade.gif[/img], 4[img]/images/graemlins/heart.gif[/img].
<font color="#666666">7 folds</font>, <font color="#CC3333">Hero raises to t90</font>, BB calls t60.

Flop: (t180) 5[img]/images/graemlins/heart.gif[/img], 9[img]/images/graemlins/diamond.gif[/img], 4[img]/images/graemlins/diamond.gif[/img] <font color="#0000FF">(2 players)</font>
<font color="#CC3333">Hero ?