3.40 KK vrs. short stack

[Master_Shake]

PokerStars No-Limit Hold'em Tourney, Big Blind is t150 (7 handed) Hand History Converter Tool from FlopTurnRiver.com (Format: 2+2 Forums)

SB (t6190)
BB (t1740)
Hero (t2750)
MP1 (t660)
MP2 (t560)
CO (t1980)
Button (t1120)

Preflop: Hero is UTG with K[img]/images/graemlins/diamond.gif[/img], K[img]/images/graemlins/club.gif[/img].
<font color="#CC3333">Hero raises to t400</font>, <font color="#666666">3 folds</font>, Button calls t400, <font color="#666666">2 folds</font>.

Flop: (t1025) A[img]/images/graemlins/spade.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 bets t500</font>, <font color="#CC3333">Button raises to t720</font>, Hero calls t220.


i was really confused on what to do on the flop... with my bet im planning on calling his AI so i should of popped it for 720 initially... was this whole line out of whack (should have raised more pre flop etc) what is an optimal line here??