Good semi-bluff spot?

Original raise was 2$ (miniraise) and everyone was calling so I had huge implied odds if I hit a straight/flush/2pr etc.
Then another raises comes around and EVERYBODY calls. I know it was 8$ more to me but pot odds and implied odds were unquestionable. Unless I flopped a nut draw/2pr/trips / some other monster I would just fold the flop.

Party Poker No-Limit Hold'em, $ BB (6 max, 6 handed) FTR converter on zerodivide.cx

BB ($148)
UTG ($26.89)
MP ($93.80)
CO ($18.50)
Button ($93)
Hero ($310.08)

Preflop: Hero is SB with 9h, Jh. Hero posts a blind of $0.50.
UTG calls $1, MP raises to $2, 1 fold, Button calls $2, Hero (poster) calls $1.50, BB raises to $9, UTG calls $9, MP calls $8, Button calls $8, Hero calls $8.

Flop: ($50) Th, Qc, 5s (5 players)
Hero bets $40, BB raises to $80

Opponents are fairly loose so I expect some action
should I have:

a) bet smaller
b) checked and hoped for small bet with lots of callers so i had odds to call

or

c) bet 40 like I did

in retrospect, my 40$ bet, although only 2/3 pot is huge for my opponents. they would either raise all in or fold to that.

so was it bad move?