I've just watched in its entirety (1h38) this wonderful 1991 video on Jack Northrop's flying wings:
At 27:45 there are some shots of the N-9MB being restored for Planes of Fame. I was lucky enough to see this amazing aircraft at Chino in 2015, in the same hangar as the Bell YP-59A Airacomet, which was being restored for flight.
Here is a nice video of the N-9MB flying at Chino:
Unfortunately it crashed in 2019:
Northrop Flying Wing N-9M Down 22/04/2019