Amongst all of the supernova, Kid is the only one portrayed to be a rival of Luffy's. The only other captain with CoC. There's no way Oda is going to miss up on an opportunity to have the two of them split the sky sometime in the future. This is why I think it is very likely that Kid is going to be a skysplitter and with big mom being his main fight of this arc, I'm willing to bet we're going to see some skysplitting feats between the two of them.
While Kid's conqueror haki abilities are still largely unknown, I think he has massive room to grow this arc. The reason being that we've yet to see any backstory from Kid. Usually in manga, backstories/flashbacks are often associated with massive power ups. With Kid being as important as he is, we still need a backstory to flesh out his character. I believe Oda is going to drop this sometime in the battle and alongside it, give Kid a massive haki bloom.
We know Kid has had a battle with the red hair pirates, so its very likely he saw ACoC first hand from shanks. If this is the case, Oda could easily use this to justify Kid getting it. We'd get the backstory of the history between Shanks and Kid, see Shanks slice off Kid's arm with ACoC, and then have Kid use this memory to unlock ACoC for himself.