2/5 NL hand - Bad play? questionable call?

[PokerCrab]

New table -- first round of blinds -- no info on players but the orignal preflop raiser has raised like first 3 hands already...he's in early position and makes it 20 -- Im on button with Jd10d...5 peeps to the flop.

Flop 2s4s9d

checked to me...I figure everyone is weak and if anyone make a real hand - they probably make a bet to protect from flush draw so i decided to take a stab at the pot -- I bet $70. I figure only callers would be A9 or some sort of flush draw.

Turn 5s

check check

I was all ready to give up the pot at this point. Figure im drawing dead if he has flush and i figure i take free card to try to beat A9 if that's why he has.

river 3s

and he checks!

that's where im questioning -- im thinking about stealing now since i can represent a straight flush or if he has a smaller flush like j or q high -- he might lay it down thinking i might have the ace. im thinking that the only hand that can really call me is the ace high flush and i didnt think he had that for some reason...so I bet 150 - is this play okay and is the bet too small or big? or is this just a bad play?

opponent calls and flip over JsQs....what do you think about this call if no reads aside from betting pattern and if you had Q high flush -- how much would you lay this hand down for?

any opinions be appreciated. =)