Valuelol

I like to flat the turn aswell.
first, that 9 hits a lot of his semibluff checkraising range, and also is a scare card for his value range, which might tighten his continuation bet frequency up a little.
if he is the type of player checkraising very wide and is on pure air here a decent amount of the times we dont acomplish too much by raising here anyways(cuz we are ahead of his pure air), unless his betting frequency is very high (cbetting thin for value + having a wide bluff range) and he can make some tightish folds here (like Q8 etc)

2nd with just flatting we can represent a wide range giving us maybe some profitable bluff spots against certain players, or giving us enough implied odds against the more aggressive ones. and having at least a bit of showdown value against some ranges ( not too sure with this though)

i can see a lot players bluffing the K, Q, once they checkraised, also most people wont check fold to a K or Q on the river, most likely they either valuebet thinly their J9 type hands here, or they just check call it.
also if we hit our flush, we stack all his good hands,
prices are okish also: 270 to win 960 = we need to realize 28% equity in this hand, given that our outs are very disguised and given that we rarely draw to the second best hand and have some showdown value and have some possible bluff opportunities (against some players) this hand is very often a call imo, very rarely a reship, and almost never a fold.
facts:
- 28% direct odds,
+ a little less than psb for implied odds
+ position
+ disguised outs (means we realize more of our equity)
+9 out for flush: ~18%
+6outs for Kq ~12%

whether to cbet or not is more opponent dependant .

gl

I am having same problem and i have been working a decent bit on it, maybe try as aleks said to take a few sec before any decision, but also remeber urself frequently that any mistakes matters. also u might try a so called mental coach, like jared tendler etc to get aware of uncontious patterns u are having