You need a photo ID to get a return to motherland permit. But kids under 11 don't have a photo ID. So first, you need to apply for a passport, then the ID is issued together with the passport. You cannot apply for an ID alone if the kid is under 11.
Book your appointment on the net and see what documents are needed. If the kid is in school, I think they need a student card or a handbook with a stamped photo.
After you get the passport with photo and ID without photo(if under 11), you can apply for return to motherland permit. But you can book the appointment on the net 1 month in advance. The photo spec is not the same as a passport, as it is difficult to satisfy the spec, most people take the photo at the China Travel Agency for $50.