25 NL Hold'Em 6-Max

SB: 100BB
BB: HERO 100BB 65
UTG: 80BB
HJ: 90BB
CO: 120BB
Button: 100BB

PREFLOP:
Fold, Fold, CO raises to 3x, SB calls, HERO calls.


FLOP (11BB):
Q65

SB checks, HERO checks, CO bets 1/2 pot, SB raises to 4x, HERO calls, CO folds.


TURN (40BB):
9

SB all-in, HERO?

I think this hand is a great one for discussion because I am never certain how to play bottom two pair. When SB raises the CO c-bet on the flop, I am putting him on hands like flush draws and/or straight draws. Being that I have bottom two pair, I am blocking most the sets the small blind could have, however being that villain flatted in the SB it is feasible that holdings could be sets of 5s or 6s. I decide to just flat for pot control.

On the turn, when the 9 comes in, I view it as a bad card because it completes some of the bluffs SB could have been raising with on the flop. Villain goes ahead and jams all-in for 2x the pot on the turn, and HERO?

I guess the two questions for discussion are:

1) How does HERO most optimally play the flop with bottom two pair?
2) How does HERO respond to 2x overjam all-in by villain on river?

I probably fold and whatev. We have better 2p

Hmmmm....blocking strong value, unblocking bluffs....a SB flat pre (so basically no QQ in range), a 4x XR...a 2x jam OTT....All parts of the story screams spazz to me. I guess im calling here and hating life

Not sure about the call pre tbh.
I know it's standard (as in everyone does it) but not sure if it's actually +EV, could be, I'm just saying I'm not sure

I'd play flop the same.

I'm probably folding turn.
I think in theory this is probably a call, since we can't have a lot of better hands here.
In practice I expect SB to show up with a set or better here almost always.

The only way we can call this is if SB shoves a lot of flush draws here, but I doubt that.
Without any further info I'd fold.