You're looking for a straight forward answer and one may not be available.
Usually, when a dependent child goes away to college, that is only considered a temporary absence from the parent's home and the student is considered to still be living with the parent, even if the student lives off campus. In the TT interview, you would answer that he lived with you all year.
In your case, the circumstances are such that he MAY not be considered as living with you. You have to make that decision.
There are two types of dependents, "Qualifying Children"(QC) and Other ("Qualifying Relative" [QR] in IRS parlance even though they don't have to actually be related). There is no income limit for a QC but there is an age limit, student status, a relationship test and residence test. He can not be your QR because his income is too high (I assume from his part time job). In order to be your QC, he must be considered as living with you. In order for you to get the $500 other dependent credit and qualify for the tuition credit (as much as $2500), you need to say he lived with you. I think the facts support that decision. He's still a kid away at school, not providing more than half his own support. You can have his address on the federal form be your address.
You also appear to be asking about some sort of state rent credit. Which state? The general rule is that it only applies to your primary residence and would not be applicable to student housing. But that may depend on the state
Book costs can be claimed for the education credit. It does not matter how they were paid for.
Room & board (rent & meal plans) are not qualified expenses for the education credit.
You do not enter anything about loans, other than loan interest actually paid.
