X-Rap,
Read the Constitution and relevant law and see how a SC justice is nominated and appointed.
Roosevelt threatened to stack the court in 1937 and that was blown out of the water.
Probability of the Circuit Judges Act (1869) being repealed and replaced to allow this, pretty minimal.
Unless the current administration has a 60% filibuster breaking majority in Senate and Congress I'm not aware about, it ain't happening.
Federal and circuit courts can and do make rulings that can affect constitutional law or serve to create case law and interpretation of the same. They do not however "own" constitutional law that is solely the within the remit of the SC who are VERY careful of their privileges.
Heller is a good example in which the SC has finally made a basis ruling on 2A but without a full clear cut set of cast in stone guidance.
For example, 2A was IMPLIED but not ruled as incorporated and in theory is only applicable to DC.
The current Chicago hand gun and the California Nordyke cases will be heard at the circuit level and will rule to act to incorporate, or otherwise, 2A.
I can almost guarantee that any incorporation or failure to agree to incorporation will immediately be appealed to the SC which will then have to make the call. The SC will either accept the appeal and make a ruling or say, in effect "We agree so we do not grant certiori."
So a lower court will have had input but cannot have final say, this is why I said, you have to now the rules to play the game.
For example if a the lower court try and leverage a pre-existing non constitutional basis law to override a constitutional guarantee it gets appealed, bounced to the SC and quashed.
I trust this answers your concerns