Do i have to claim my child as a dependent

We are married parents with a son in college and we pay more than 50% of his support.  Our AGI is above the level such that we don't qualify for the American Opportunity Tax Credit, the Lifetime Learning Credit, or the federal child tax credit.  Our son has to file is own tax return for the income earned from a part time job.  Can our son claim himself when he files his tax return?

 

Is the choice up to us or is there a requirement that we have to claim him as a dependent?