9.5 inch is fine in a #10 cirkut. The 10 was designed to use any film between 6" and 10", and a lot of people used 8" B&W film in a 10 cirkut when they stopped spooling 10" B&W film, or when they didn't need a 10" wide neg. You just cut the spools to fit the film. I make a jig to cut spools and glue them so they are all consistent.