It was written, produced and directed by Ed Wood (go rent the film of the same name by Tim Burton for some background).
In any case, if ever there was a film that was ripe for a remake, and one of the very few projects I would get behind in this regard, this would be it. But no, the studios are too busy doing remakes of lame 80's TV shows instead.
The cool thing about a remake of "Plan 9" is that it could go in either of two directions: It could be made on a shoestring, with the attempt to recapture the unintentionally funny spirit of the original, or the basic story could be turned into a real horror/sci-fi film. I mean it's got the elements, right? Re-animated corpses, aliens, spaceships...
Come on folks, somebody throw a script together and get busy!