PS $5.50 10bb TPTK, if not push then?!?!

[Beerocrat]

I got some criticism of this by a friend who is more experienced than I. I guess I have trouble on the bubble when I am ~10BB. If a push is not correct here, what is?

PokerStars Tournament, Big Blind is t200 (4 handed) Converter on pregopoker.com

CO (t5960)
Button (t3240)
SB (t2510)
Hero (t1790)

Preflop: Hero is in BB with A[img]/images/graemlins/spade.gif[/img] 9[img]/images/graemlins/heart.gif[/img]
<font color="gray">CO folds</font>, Button calls t200, SB calls t100, Hero checks

Flop: (t600) 4[img]/images/graemlins/diamond.gif[/img] 9[img]/images/graemlins/spade.gif[/img] 8[img]/images/graemlins/diamond.gif[/img] (3 players)
SB checks, <font color="red">Hero...