10nl 6max: 99 in the CO against MP raise (what to do if flop overpair)

[a nonymous]

$0.10 BB (5 handed)

BB ($10.15)
UTG ($9.25)
Hero ($17.95)
Button ($10)
SB ($15.05)

Preflop: Hero is MP with 9[img]/images/graemlins/diamond.gif[/img], 9[img]/images/graemlins/spade.gif[/img].
<font color="#CC3333">UTG raises to $0.35</font>, Hero ?

I had played 67 hands with UTG, he had 6.0 VPIP and 4.5 PFR numbers. (Is this a call?) I'm pretty certain it's a call, so my real question is, what do I do if I flop an overpair?