Villain is playing 45/9. No reads on him, what now... what do we figure he is holding?

No-Limit Hold'em, $0.02 BB (5 handed) - iPoker Converter Tool from FlopTurnRiver.com

Hero (UTG) ($1.13)
MP ($1.89)
Button ($1.73)
SB ($3.21)
BB ($1.18)

Preflop: Hero is UTG with A, J
Hero bets $0.08, 1 fold, Button calls $0.08, 2 folds

Flop: ($0.19) 4, 2, A (2 players)
Hero bets $0.09, Button raises to $0.23, HERO???