Six player NL cash game. I'm on the button and hold KK spades and clubs. We all have roughly $250.

Action is folded to one from the button who raises to 4 x BB. I suspect a position raise as he often raises from the button or one from the button; I don't want to scare him off with a reraise as I've got position on him so I smooth call, knowing that the BB is very tight and will fold all but huge holdings. SB raises to 8 x BB, which I didn't expect. BB folds, one from the button calls. Now I'm wondering if I'm up against AA and so I don't re-reraise but call, intending to dump the KK is an A flops.

Flop is QT2 all spades. SB bets half the pot, one from the button folds. I consider coming over the top but now I am doubting that he has AA as his bet is weak, and I can't put him on a flush. So with an overpair and 4 to the K flush I smooth call, risking an A on the turn.

Turn is a rag. SB bets the pot. There is now about $200 in the pot with this bet and I have about $200 left. I might possibly be ahead. If he has AA then I am behind, but as long as one of them isn't A spades then I can still hit a spade or a K. If he has trips I can hit the same to win. And I figure that I might make him lay his hand down if he reads me for a flush or a big hand.

So I move all in and he folds, not showing what he was holding.

Any thoughts on the all-in move? I know it was risky but there were a lot of hands he could have put me on. I'd love to know whether or not he folded the best hand.