Based on the information provided, your 22-year-old is a dependent. A full-time college student under 24 can make any amount and still be a dependent. You would just need to provide more than 1/2 of his support, and you indicated this was the case.
I suggest revisiting the interview section and making sure that all the information is correct, in case something was accidentally missed.
Navigate to My Info, Your household, select your son's name.
- Choose "My child", continue and be sure their name, date of birth and proper citizenship is complete.
- Continue, and answer the question about living arrangements and parents.
- Continue, and answer any less common situations, if applicable.
- Lastly, enter the his SSN and be sure that "Not valid for employment is printed..." is NOT checked.