Again, since he didn't push for it, lobby for it, or do anything whatsoever to try and get it passed then it's obvious he wasn't serious to begin with.
What evidence do you have of this? What documentation do you have that Davis withdrew his support for a supreme court? That's right, non-seq. In your usual fashion you have nothing.
For the time being I will simply note that a bill to establish a court certainly did come before the confederate congress and was a subject of several debates, so obviously somebody did push for it.