You could modify the course format to topics, then add a certificate plugin to the bottom of the course and then switch it back to single activity - but you would still have issues trying to display the certificate to the student after the SCORM is complete.
I have seen people embed certificates into their SCORM activity - (not using Moodle certificate, but just generating an image within the SCORM and getting the user to print it.)
You might also consider using Badges and just give the user a Badge on completion.