I have been filing my taxes for a very long time; I'm talking almost a decade. I can tell you with 100% certainty that you can use your own SSN. The purpose of an ITIN is to provide a way to file taxes to those without a valid SSN.

For the purpose of filing and paying taxes, it is irrelevant wether work authorization was granted or not. The number is a VALID number issued by the agency, and belonging to you.