opp is something like 12/8/9 after a couple hundred hands. How do you react to this minraise?

Party Poker No-Limit Hold'em, $ BB (5 handed)

Hero ($109.20)
BB ($97.70)
UTG ($168.10)
MP ($110.83)
Button ($152.04)

Preflop: Hero is SB with Kc, Ad. Hero posts a blind of $0.50.
3 folds, Hero (poster) raises to $3, BB calls $2.50.

Flop: ($7) 2s, Ah, Ts (2 players)
Hero bets $4.5, BB raises to $9, Hero???