Consider what your overall c-betting strategy is for this flop. If you might c-bet 99 as the middle player of three on this flop, what else are you c-betting? What are your bluffs? How are you going to ensure your checking range isn’t face-up? Does it even matter if your checking range is face-up here?

These are all questions that need to be answered before we can figure out if betting is optimal with 99.

I misread the spot, I thought you were the middle of three players but you’re the 3rd of 4. That accentuates most of my flop concerns.

Few more questions:

1. What factor is it that leads you to want to bet JJ, but not 99?

2. When you bet flop and get called, which hands are you bluffing with when the flush completes the turn?

3. What factor is it that makes you prefer check-raising (I assume you meant to write check/raise GII) with Tx, while betting with JJ+?

4. Going back to preflop, what factors make 22 a raise for you here preflop while hands like T9s and A5s are folding?

5. You seem concerned about your high check-folding frequency on this flop. This indicates you’re worried villains might exploit it, and suggests you’re trying to construct an optimal, less exploitable strategy here. If this is the case, don’t you think we should do something about those extremely value-heavy betting and check-raising ranges first?

Either those betting and check-raising ranges are perfectly fine to exploit our opponents’ tendencies (meaning check-folding a lot is also fine as an exploitative strategy), or we need to balance both our betting ranges and our check-folding frequency. I don’t see a scenario in which we’re totally okay with being really unbalanced with our betting ranges, but really paranoid about our check-folding frequency being exploited.

I think c-betting some different types of hands would probably be okay, but it’s not easy to increase your c-betting frequencies multiway. I think your best approach here when squeezed in the middle of four players is just to check your entire range, and then build c/c or c/r ranges according to the action in front of you. You’re having enough trouble balancing a betting range here that I think you would benefit from removing it entirely.

almofadinhas said
Very good questions! Here we go:

I like the idea to remove all my cbet range on such spots and acting depending on the action from other players.  

For some reason your full post hasn’t been quoted here and I can’t get it to appear, but I’ll address a couple of points:

1. If you haven’t thought about why you would be betting an overpair here and not 99, then this is where your problems are coming from. You’re autopiloting these spots too much.

2. My point was that if your flop betting range is narrowed to value and flush draws, you simply have no bluffs on some turns. But if you expand your flop bluffing range, you might be bluffing too much. This is why multiway spots are tricky.

3. Having no c/r range here is most likely better than having purely value, so this is good to hear.

4. What’s easiest isn’t always the most profitable. A5s and T9s are better hands to open than 22-44 in almost any spot – there shouldn’t really be situations where you’re folding those hands but opening 22. If you find those hands difficult to play post, you’re probably not playing them aggressively enough when you flop draws, or playing them too aggressively when you flop pairs.

5. I think never c-betting OOP multiway would benefit you greatly in the short term. It would certainly make this specific spot a lot easier.