Do I still need to include my grown son (21 years old) who did not live with us at all this year and got married? Can I delete him off my taxes or do I keep him?

It depends.

The first rule is, if your son files a joint return with his wife, or if he has a dependent child of his own, you don't claim him as a dependent.

If your son doesn't have income and won't file his own tax return, or will file as married filing separately, then he could be claimed as a dependent if he meets the usual rules (lived with you more than half the year, did not provide more than half his own support).

However, you would receive at most a $500 tax credit, and asking your son and his wife to both file married filing separately could cost them more than $500 in higher taxes.