KQ should probably 3b preflop, but your line is reasonable. However I don't think I like your sizing, what are you trying to target with this sizing? I think I would bet bigger or smaller, possibly both with some parts of my range.

looks fine, reasoning is fine, i would be a bit concerned that his river range might have too much Kx+ that he decides not to fold to attempt bluffing tho

Generally FD hands really suck for barreling but with rivered 9x being poor bluffing hands (they beat 8xdd, Ahigh fd) I think it's pretty mandatory to bluff this one.

imo if nit calls u preflop, his range gonna be tight, and if he calls u OTF, i would be in giveup mode, or maybe x/c turn dependant on odds

btw he will have i guess a lot of KX in his range after he called F or wut do u put him on after F call?

u block some FDs he could have so theres lesser chance he missed, and rather have made hand like KX, tho theres still a lot of AdXd which he might have all maybe, so after u went doublebarell, u can triplebarel this R i guess

but still i would prefer something like x/c or x/r F i guess , but cbet aint bad either since ranges are wide BBvsSB and u can haz some FEq

I wouldn't call a 19/15 a nit

Body, the board is not scare enough. If BB calls on flop and turn, he won't think you have 75 or 7T.