There is another potential issue here.  The original post says dad isn't claiming son because of the divorce decree.  If the son is emancipated in the state where they live, the divorce decree should be irrelevant. Dependency will solely be determined on the other rules as listed in Pub. 501 without any regard to rules for children of divorced or separated parents, as those rules no longer apply.

So if son is living with dad and emancipated under state law, assuming the other conditions in Pub. 501 are met, dad would get the exemption and the college credits if his income is not too high.  However, he still would end up with some income from the 10099Q if he claims the credits.