Can your 13 year old watch your 9 year old?

In Canada I don't think that there is really a legal age to babysit. It is up to the parents. I know many 13 year old people that babysit 9 year old children and it has turned out fine. But it also depends on the child who is babysitting. If the parents feel that he or she is responsible enough, there should be no problem with them babysitting a 9 year old.