The typical cognitive assessments that are used for children require them to be able to use their hands to point to pictures or hold puzzle pieces.
For a child with CP learning to move, the really important things to remember are that the child should always be active.
Every educator needs to make a decision about technology they need to put in place. They're not sure if they should put Option A in place or Option B in place. This can be particularly difficult in the world of disabilities because there might not always be a perfect answer. Teachers can look to this solution, using the least dangerous assumption to make good decisions about what technology might be best.
When you don't have enough evidence about a student's performance, assume they can do whatever you're asking them to do.