PokerStars No-Limit Hold'em, $0.50 BB (6 handed) FTR converter on zerodivide.cx

UTG ($53)
Hero ($49.50)
CO ($9)
Button ($4.75)
SB ($159.80)
BB ($14.20)

Preflop: Hero is MP with K, K.
UTG raises to $1, Hero raises to $3.5, 2 folds, SB calls $3.25, 1 fold, UTG calls $2.50.

Flop: ($11) 8, 6, 9 (3 players)
SB checks, UTG checks, Hero bets $9, SB folds, UTG raises to $18, Hero calls $9.

Turn: ($47) A (2 players)
UTG bets $31.5 (All-In), Hero folds.

Final Pot: $78.50

Ok; my reason for folding on the turn rather than the flop; I wanted to see the turn (heart?) and see what his action is. To me this felt like a flopped set rather than the flush (9s?)... thoughts?

Very tough hand to laydown, but it's not invincible and I felt I was behind with only about 10 outs. Should I have folded on the flop? Comments on my play please