My DD9 is doing exactly what you propose only we pay for the courses. She is in private school however. She is miles ahead of the grade level curriculum in language arts so she onlines at school for 2 hours per week. Giving your DD more work is not enrichment, nor is it differentiation. It's just more work.
Anyway, excellent online language arts enrichment exists online. Your DD has already found some so good for her. My experience is that the less resources you propose to use at a reluctant school the more flexible they will be. Good luck!
