Move floor vent into the wall
This should not be a problem. As far as I know, code concerns itself with how much airflow is available for each room, but whether it comes out of the floor or the wall shouldn't make a difference. All you need is something like this rectangular elbow:



As long as you can find the right size to match your existing ductwork, this is really easy. If you can't find the right size at a big box store then try an HVAC supplier - the place the HVAC techs go to get their parts. If you know exactly what you need, they should be happy to help.