I dunno, shimano/SRAM chains are subtly different now*, I’ve no idea which way KMC aligned theirs, presumably for the roadie market, but I’ve no idea which of SRAM/shimano transfered the dimensions from road cassettes/chains to MTB.
Does anyone else still do it the old fassioned way, press the pin through the inner link, then push it back again to re-fit it? Supposedly weaker, but since going 1×10 I rarely have to multiple shift in a hurry so the chain’s not bent as much.
On the other hand plenty of people seem to get allong fine with a 9speed link.
*one kept the sprocket thickness from 9speed cassetts and made the chain plates narrower, but the inner width is the same, the other kept the chain plates the same width and narrowed the sprockets so you theoreticaly have to match “chains and cassetts”, and “mechs and shifters”, but the mechs/shifters dont need to match the chain/cassette.