No, the case taper between 9mm and 380 is different. You need to use a 380 sizing die (preferably carbide). Also the 380 casehead is slightly different than that for 9x19 parabellum/luger (aka normal 9mm). The 380 casehead is extremely close to the 223 casehead in size.
If you have a dillon 550, use the shellplate and buttons for 223 with the expander/drop tube for 9mm. Use 380 dies; it really is a different cartridge/case than that for typical 9mm.
The bullet diameter between 9mm and 380 is the same; just use lighter weight bullets (~102 grains or less) for loading 380.
