99 in big pot

[kurosh]

I raise 9s 9d UTG
brazilio 3-bets on the button (TAG), we haven't been screwing around really
unknown SB calls
loose passive BB calls
I call

Flop 4s Th 6h
check check, i bet, brazilio raises, everyone calls

turn 4d
check check, i bet, brazilio folds, sb raises, bb folds, i...?

The move was very strong... but the pot is big and he is unknown.