Hit set but flop is draw heavy: did I protect or wimp out?

Not really enough hands to get reads yet. Mostly loose-passive table.

Party Poker 0.50/1 Hold'em (10 handed) FTR converter on zerodivide.cx

Preflop: Hero is MP1 with 9[img]/images/graemlins/heart.gif[/img], 9[img]/images/graemlins/club.gif[/img]. UTG+2 posts a blind of $0.50.
UTG calls, <font color="#666666">1 fold</font>, UTG+2 (poster) checks, Hero calls, MP2 calls, <font color="#666666">3 folds</font>, SB completes, BB checks.

Flop: (6 SB) T[img]/images/graemlins/spade.gif[/img], 9[img]/images/graemlins/spade.gif[/img], A[img]/images/graemlins/spade.gif[/img] <font color="#0000FF">(6 players)</font>
SB checks, BB checks, UTG checks, UTG+2 checks, Hero checks, MP2 checks.

Flop is scary for my set, since any spade has a flush draw, plus there are many straight draws possible. I figure betting now will make every draw call and give them good odds to call again on the turn. My only hope of protecting my hand is to bet or raise a safe turn and hope to get the draws out, leaving only Ax or maybe Tx. I thought this might work with an EP limper in front of me who I hoped had an A or T and would bet, allowing me to raise.

Turn: (3 BB) 3[img]/images/graemlins/diamond.gif[/img] <font color="#0000FF">(6 players)</font>
SB checks, BB checks, UTG checks, UTG+2 checks, <font color="#CC3333">Hero bets</font>, MP2 folds, SB calls, BB calls, UTG folds, UTG+2 calls.

As you see it was checked to me. At least my bet still cut down the flush chasers odds more than a flop bet. I did get some folds, as I had hoped. I do realize that flush draws can still call here, but the call isn't as profitable as it would have been if I had bet the flop too, and had I been able to raise, it would've been unprofitable.

I still feel wimpy for checking the flop, though.

River: (7 BB) A[img]/images/graemlins/heart.gif[/img] <font color="#0000FF">(4 players)</font>
SB checks, BB checks, <font color="#CC3333">UTG+2 bets</font>, <font color="#CC3333">Hero raises</font>, SB folds, BB folds, <font color="#CC3333">UTG+2 3-bets</font>, <font color="#CC3333">Hero caps</font>, UTG+2 calls.

The A most likely makes the EP limper trip As or he slowplayed the flopped flush, so I happily cap with my boat.
Final Pot: 15 BB

So bet or check on flop? Definitely bet turn, right? Pretty easy, but I don't know if giving a free card on the flop is better or worse than the EV you gain by cutting opponents odds more by the turn bet into a smaller pot.