using fusion 360

I have already downloaded Fusion 360 (for free because of the educational license) and the Vex EDR parts. Would it be a waste of time to create a model of our robot in Fusion?

Definitely not, not only does it look great for your notebook, but when we made a CAD model of our robot we were able to predict problems we were going to face beforehand and solve them earlier too. Although I would recommend you to use solidworks only because there is a feature on GrabCad that makes it easier to collaborate on the robot. Hope this helps,