I am not sure I have anything helpful to add, but I wanted to add my support. Also, I think 9 is a tough age, especially for a girl. Female relationships start to become very, very complicated.
I do wonder if she is unaccustomed to being fully challenged and is experiencing stress over the added challenge. While it is very common for kiddos to be G&T ID'd at this age, they have already had several years of "easy school."
DD8 can be VERY emotional and dramatic at home, but she has always been rather intense. She, too, was tested this past year (extensively), and so she might be encountering added challenge due to programming changes. Suddenly, she is getting more homework (I would prefer it was different, not more, but that is the subject for another thread). At times, she seems angry, too. I am not sure what is causing it, but I am constantly trying to figure it out...so you are not alone.
Perhaps someone who has an older DC, who had "challenge" added at the age of 8 or 9 can comment on how to best help a student adjust to this?
