You can use a regular DINSE adapter to hook up your torch. I believe it's just not the safe loc from CK as the plastic housing is too big. The Weldcraft one should fit just fine I believe the part number is Q5G-150 for WP-9. No idea why they didn't sell you that as a DINSE package from Weldcraft. CK offers the correct quick release fitting for the argon as a plug and play setup, where with Weldcraft you will have to transfer the one from your old torch. There are always ways to make things work, welding machines are getting more and more standardized all the time, but there is still some room for improvement. Torch makers still sell cables that fit nothing, out of the box, and require installation kits for each brand. Someday I hope they start offering cables with DINSE factory terminations. They would be a lot more compact and durable than the huge adapters that are required now. Almost all brands have gone to DINSE, with only a few hold outs.
BTW: if you really want to use the CK safe loc plug, I bet you can do so with a short male to female DINSE whip cable.
Long arc, short arc, heliarc and in-the-dark!