Once upon a time, it was officially ruled legal to utilize the partner port to connect to other devices in VEX U:
The idea is that, no matter what/how you interface the keyboard and mouse with the robot, the Brain is still the only thing along the chain that directly operates the robot. That is, competition control and software on the Brain can at any time completely override any external inputs, and the external inputs have no effect on the robot without the Brain’s software interpreting those inputs.
Though this should definitely be clarified in this season’s Q&A if OP wishes to utilize the partner port in this manner for VEX U.