As the mom to four kids I always had 5 daycare so 9 kids was the norm. And for a few summers I had two kids over 10 that were siblings of kids in care. I just considered it normal. It is amazing that it doesn't seem like all that much more work since you are doing most of it anyways. With that many there would be age restrictions so I didn't have 9 in diapers at a time - just 6.