Can I (as a minor) create a contract for IP and sign it.

It's not so much a matter of whether it's legal as whether anyone you hope to do business with will accept it.  Generally a contract with a minor is voidable at the minor's option, meaning that, if the contract turns out to be a bad deal for you, you can back out of it, but if the reverse was true, the other party is still stuck.  Obviously, anyone  you do business with will want you to be bound to the contract as they are, and therefore likely will only contract with an adult.