It's hard to place Zoro considering he didn't show Ashura yet.
But yes it's clear that he is above scabbard.
His portrayal against Kinemon and Kawa indirectly hint so.
As Zoro is taming enma which only oden was able to do so,his Haki will develop further.
If Zoro cuts Kaido without making it a black blade then Zoro is comparable to oden (no need to tell the hype oden enjoys)
But if he cuts Kaido, after making enma black then Zoro >oden because the latter didn't do so.