He was indeed appointed to the bench by President Clinton. He may have been assigned to be one of the judges sitting on the FISA panel by Rehnquist but Rehnquist would have no authority to have to put him on bench. Judges are appointed by the President and seated upon confirmation by the Senate, per the U.S. Constitution.
But it's up to Rehnquist to staff the FISA court. If you want to blame someone for this guy being on FISA, blame Rehnquist, not Clinton. Rehnquist didn't have to pick this guy, he could have picked anyone.