If they didnt support themselves they probably still qualify as a dependent (even if they're not claimed as one, they still qualify as one) and wouldn't be entitled to the RRC, and apparently dont qualify for the refundable school credits either.

Thank you Just-Lisa-Now, I page 2 of Form 8863 instructions under "Who cannot claim a refund" does not mention age. On page 6, Line 7 the information is explained. Sorry! to Community for any waste of your time and thanks again Just-Lisa-Now!  

"because many college students are claiming themselves in order to get $1,800 Recovery Rebate Credit and the $1,000 Education credit will bring credits to $2,800."

Work through the Dependency wizard.

You use the 2020 return to reconcile what a person is entitled to, against what they got.

If the person is not a dependent in 2020, then they would be entitled to the payment/credit as individual filers. That doesn't mean "not being claimed." It means "no longer qualifies as a dependent."

You might want to bookmark these links and read the IRS guidance.

Interactive wizards portal for determining dependency:

https://www.irs.gov/help/ita

And:

https://www.irs.gov/newsroom/economic-impact-payment-information-center-topic-a-eip-eligibility

https://www.irs.gov/coronavirus/second-eip-faqs#Eligibility

One for each EIP.