I don’t personally don’t believe that his df is going to be shafted even if he unlocks adv CoC. Also, why would Oda reveal that Kidd has CoC earlier in the arc if we aren’t going to see him do anything with it on screen? If Luffy and Kaido both are clashing their conquerers spirit in their fight, I would expect Kidd and Big Mom who are also conquerers to be doing the same in their fight.
They may have a COC clash, but I don't expect anything on Luffy/Kaido level. I mean it's implied that you need Ryou to understand the concept of coating your attacks in CoC and Kid didn't even have an idea what haki Luffy was using with Red Rock. I think going from that to using CoC coated attacks would be too wild, but then again, this is Oda. He might pull wild shit like that.
I just hope Kid is a devil fruit based fighter, I see nothing wrong with that. My headcanon for him coming to the raid was that he attracts all the metal from the weapon factories of Wano and pulls a mini Bullet. We know Kid likes Robot armors and we know having more metal is good for him since he carries it around.
It would be an insane display of AoE and would symbolically end the days of Wano manufacturing weapons.