(Depending on the size of town) Some towns have "after school programs" for kids. I don't think a 9 year old kid is mature enough to be left on their own for 3 hours every day. Many times there are programs & services for low income familes to take advantage of regarding child care. I think it's your business as a landlord to get involved. Talk to the mother, or seek out some possible resources for her and tell her about them.