The President has plenary authority to declassify absolutely anything. And plenary authority to send as many Marine Divisions and/or National Guard units as necessary to enforce his EO’s. He could have CIA and/or NSA headquarters taken over by the military, or simply bombed into non-existence.
In fact, the CIA is the only civilian US intelligence agency. All the others are military agencies, and cannot lawfully disobey a Constitutionally-valid order from the US military Commander In Chief.