2/5 round by round nlhe/plo Very fishy table

V1- older guy, extensive history, very mediocre. Taken many big pots from him tonight and he's been after me betting/raising any hand I'm in. Double/triple barreling with air if I'm in hand and showing multiple bluffs. I've caught him quite few times today as well. Opening nlhe pots 5x nearly every hand in every position for last 3 orbits
Stack- $700

V2- guy in mid 40s. Just sat down at table. This will be his first hand. Not a ton of info, but from playing a little bit in past seems decent. Not great but probably average.
Stack- just sat at table with $2400


Hero- young aggro lag kid who's been running over table, but just lost huge $1200 pot aa vs kk ai pf. Flop kxx.
Stack- 725

Folds to v1 in HJ.
Makes it 25
V2 calls. In cutoff

Hero Qh9h- calls (yes probably a fold, but fairly sure could be ahead of v1 opening range, and if hit, going to be able to stack v1)

Flop Qd9s7h
V1- bets $50
V2- raises to 150
Hero- ??? I elected to flat call. V2 also has history with v1 and could be making a play?

V1 calls.
turn 2c

V1 check
V2 bets 250
Hero-??

I would fold pre.
As played, shove. With Q9 on the turn. You say you called pre to make a big hand and win a big pot. Top two is about as good as you could get. You can't be scared of a set here. You can't be scared of QQ, there's only one combo of 99. If V1/2 has 77 it's a bad beat. Happens. V2 /V1 could have a weaker two pair, set, AQ,KQ or s straight draw. Your ahead of most of their range.
While you're ahead, get the money in.

Flatting flop is good. As played, it's a must cram.

Yes, fold pre. I'd reraise on the flop. A cold call is already really strong. Why give V1 decent odds to call with some kind of draw? GG if V2 has one of the five set combos. You're doing well against 16 AQ/KQ combos.

If v1 did the turn bet, I would not be worried at all
But v2.. My flop call should be yelling strength. I think v2 would slow down with tptk?

I think you have to be ready to gii by the river when you call the flop raise. However he could be trying to iso v1 otf. The turn bet is trickier but you need to know what your gonna do when you call the flop raise. The turn bet is less than half lot so it's not a huge bet, the pot is just bloated. Don't see how you lay down top 2 for a <1/2 pot bet.