N9845L is taken. It's currently assigned to a 1986 Cessna 172P registered in Nantucket, MA.
See the full aircraft record →A tail number only frees up if the owner deregisters the aircraft or moves it to a different N-number — and even then the FAA holds it before releasing it to the public.
N9845L has been worn before. Past registrations from FAA deregistration records:
Tails one nudge away from N9845L that aren't assigned or reserved: