Its close, not so sure if these players bluff enough like this.
We have a good candidate not blocking spades, Like id prefer this over KT with a spade. Think you can go either way really depending on player pool

Whats your sn op? we prob have played a bunch vs each other but I dont know who you are. Agg% per street would be much more relevant info. That said, there is only one player profile capable of bluffing enough in this line so if you don't have any other read folding should be the best play

How balanced is the player pool when betting small on this run out? I’m leaning towards a call here since we block 8’s and I could see a lot of bluffs that play the hand the same way. The more I look at it I don’t think I could fold.

Between call and fold we're too weak to call. If you're calling KT+ though, would K9o not be an ideal candidate for an occasional c-r bluff here? Open to opinions.

I believe it's a call unblocking spades. Even though having two spades for pfr isn't that good to bluff river but on this runout it's hard to have other bluffs than missed flush draws, so even optimal play for pfr should be bluffing more missed flushdraws than ussual on other run outs(I THINK:D). I believe better play should be to fold even as strong as K10 with a spade, and call off most of your kings with no spade. And even that might not be enouth, so u should call some of ur a3 combos I think (for sure those who unblock spades). Ps. Im just guessing here:d

I runned a pio. Pfr bets on the river is mostly shoves (2x+ overbet) with trips plus, and bluffs are low missed flushed draws and straight draws, and some random air who was mixing bets on turn (who doesnt block spades), OOP bluffcatching with almost all 8 (just 84s mixing fold and call),and K2s,K4s are always calling Pio uses 4% of small sizings witch includes like AA, quads, and very few 8's, with bluffs of very random air (but not flush draws), so for oop when blufcatching having a spade is bad against that small sizing. But I runned just because I was curious how it plays out against optimal play. I still do think that against this player bluffcatching with no spades in hand is best