PokerStars No-Limit Hold'em, $0.25 BB (8 handed) Hand History Converter Tool from FlopTurnRiver.com (Format: FlopTurnRiver)

MP1 ($16.10)
MP2 ($25)
CO ($17)
Button ($33.30)
Hero ($14.25)
BB ($24.40)
UTG ($20.20)
UTG+1 ($14.75)

Preflop: Hero is SB with K, K.
1 fold, UTG+1 calls $0.25, MP1 calls $0.25, 3 folds, Hero raises to $1.25, BB calls $1, UTG+1 calls $1, MP1 calls $1.

Flop: ($5) 8, 9, 6 (4 players)
Hero bets $3, BB raises to $13, UTG+1 calls $13, MP1 calls $13, Hero ?????

Do I put someone on AA here or a set? Possible flush or str8 draw. Getting almost 5/1. Call or lay down?? New to table. Only 3-4 hands seen and they have been semi loose.