When and where was my Buffet Crampon Everett alto sax made the serial number is 609488 it has no other markings or letters on the body?

Your Buffet Crampon Everett Alto Saxophone with the serial number 609488 was likely manufactured in the year 1977. Buffet Crampon typically produces their instruments in France, so it was likely made at their factory in Mantes-la-Ville. For precise information about your specific instrument, you may want to contact Buffet Crampon or refer to a Saxophone expert.