I assume that he is a full time student which would allow him to be claimed as a dependent or else qualifies as a qualifying relative.
If you don’t have another child living with you then you can’t file as Head of Household on federal or CA returns. Only the custodial parent—even when not claiming the dependency—can file as HOH, claim earned income credit and child care credit if otherwise qualified. You as the non custodial parent claiming the dependency can only receive other child tax credit of $500.
