Good morning.I agree with Giac. However I'm not one to take students that young, and I usually refer younger students to a very good local teacher that will take them (or put them on a waiting list). This isn't because I can't or won't teach them, but because this other teacher has a superior kids program, and I prefer older students. I'm sure he doesn't mind the referals.
I hate the thought of discouraging anyone from playing guitar, but I still believe there's serious physical limitations before age nine that can only be overcome by a small scale instrument with soft (ie, nylon) strings. It's not the understanding of music or even the coordination that's the issue, it's simply the size relative to small hands. The size of the instrument, the size of the strings, the size of the string tension and so on. When a parent once exclaimed that her kid couldn't play mandolin despite its size, I had some difficulty explaining that the tension on mandolin strings even makes it hard for many adults.
Lately I've seen some South American half and 3/4 guitars with nylon strings which were quite playable, and quite affordable. Brazilian maybe? But be careful, these things don't get alot of respect in some music stores, and may need some setup attention before they're purchased.
My two cents, but I'd like to hear other opinions, as I'm thinking of accepting younger students, so as to decrease my dependence on a second job, and teach ME something.
Peace, Mooh.