($16) Flop top pair vs donk limper

[beserious]

This guy limped once I think at 25/50 early. Probably doesn't have a monster, but I've come to the conclusion that pushing pf here with A9o is -EV because AT+ and any pair is instacalling. How do you play the flop/turn?

PokerStars Tournament, Big Blind is t150 (7 handed) Converter on pregopoker.com

UTG (t1960)
UTG+1 (t4055)
MP1 (t1310)
CO (t1465)
Button (t525)
SB (t2660)
Hero (t1525)

Preflop: Hero is in BB with A[img]/images/graemlins/heart.gif[/img] 9[img]/images/graemlins/diamond.gif[/img]
<font color="gray">UTG folds</font>, UTG+1 calls t150, <font color="gray">MP1 folds</font>, <font color="gray">CO folds</font>, <font color="gray">Button folds</font>, <font color="gray">SB folds</font>, Hero checks

Flop: (t375) A[img]/images/graemlins/diamond.gif[/img] K[img]/images/graemlins/spade.gif[/img] 8[img]/images/graemlins/diamond.gif[/img] (2 players)
Hero checks, <font color="red">UTG+1 bets t300</font>