You could certainly ask the school for an OT assessment, especially if it's free, and see how far you get. If your insurance covers an OT assessment, then that might be something to consider as well.
I understand what Polarbear is saying; however, writing involves eye-hand coordination as well as motor skills. At this point it seems difficult to determine what is going on. Perfectionism and a 7-yr-olds in general who may not always be motivated to perform to their abilities may also be factors here.
So you might try to rule out/in other factors first before going to a behavioral/developmental optometrist.
