On a basic level, probably not a 'problem' that a 9 y/o (or 12 y/o...) can't read - but mom & dad won’t always be there to read for her.

Then her 6 y/o cousin comes to visit and can read better, and crushes her confidence.

The idea is lovely - Let kids be kids - but I witnessed several kids go through this kind of program and while they are very socially adept (compared to all the Autistic kids running around), they now need some intense intervention to get up-to-speed on basic reading & writing, because nobody was qualified to help them when they first showed interest.