Delete the dependent and re-enter him. Answer the dependent interview questions carefully, particularly the ones about the other parent possibly claiming the student.
Everything you describe says you can claim him and the credit. If he is away at school, still say he lived with you all year (college is only a temporary absence from the home), unless he lived with the other parent.* Be sure the half time or more student box is checked at the 1098-T screen.
*If you are the non-custodial parent answer that you have an agreement with the other parent and are claiming him (or the other parent has waived their right).