The shuttle was originally intended to be launchable into polar orbit from Vandenberg AFB, but it never happened [0]. I rather doubt anybody ever seriously contemplated a transition to polar orbit from a Florida launch; the shuttle couldn't carry enough fuel for that. (One cannot launch a rocket into polar orbit directly from Florida for safety reasons. That's what Vandenberg is good for; there's no inhabited land south of it.)

[0] https://www.thedrive.com/the-war-zone/27506/vandenberg-afbs-...