WSOP $1500 ITM -Top 2 in huge 3-way pot

[MUD]

220 left in WSOP $1500. Average stack is 30000. We're ITM and the money doesn't really start jumping until top 50. Big stack in this hand plays really passive. Limps some (limped JT from middle position in one spot), minraises a little and has shown down stuff like A8o, and raises to 4x BB with big hands. He actually said something to the effect of "if I raise big I have a big hand" and has shown AA when raising 4x BB. The table is calling him "Terminator" and somebody mentions him winning 6 straight races when I get to the table.

Mid stack is playing more straight forward. Although he has called one of these minraises from the BB before and just bet out and taken the pot. I have yet to see him cold call a raise in position but all my time with him was around the money bubble. Overall he has been solid TAG but hasn't shown anything down yet.

I had been really aggressive around the money bubble because the big stack was so passive. I had stolen my way from 30000 to 50000 while losing 2 showdowns to short stacks. I had led out from the SB for half pot on the money bubble in a limped pot on a steal.

Big stack 90000
Button 38000
Hero 45000

We're the 3 biggest stacks at the table.

800/1600 ante 200

The Big stack minraises to 3200, button calls, SB folds and I have Q9o in BB. I call.

Flop Q9s8s

I lead out 7500, big stack calls almost immediately, and button almost immediately goes all-in for 35000. Button seems strong, and big stack is kinda of shaking his head looking at his chips(he doesn't see me watching him and I am 99% sure he's not tricking me, he plays extremely non-tricky).

Pot is now 34000 and its 27000 to me, and I have 34000.

All-in or fold?

Do you guy like preflop? how about the lead out?