Interesting!
I tried the needle nose pliers, as it seems the Park tool is basically a pair of pliers designed to hook the links, but that did not work so my conclusion is that this is one of the 8/9 speed chains that is not made to be unlinked with this link. What puzzles me then is the remark that these chains are not meant to have a pin pushed out and reinserted. I cannot find anyone who sells pins for the KMC chains like Shimano so either you must use a Shimano pin then or use some other external connecting link like the Wippermann or SRAM, is that correct? Times have changed I know but time was the only way to break a chain was to punch out a pin until you could unlink and then reinsert the link. What's the experience out there on doing this to a KMC chain, purportedly 8 speed?