SOLVED. Young Adult book about 2 teens with "imaginary friends" that wreak havoc. [s]

[Emma]

The main character is a teen girl dancer and she
wants to be a Rockette. She had this scary imaginary friend named Rachel that destroys things. The other character is a teen boy from a broken family and his imaginary friend is a monster. They figure out they had tests done on them as kids and that's why they have these imaginary friends. Then they figure out they can control their friends. I think the first scene is on a bus. I read it in 2012 I think so written before then.

[Becca]

Damage by Anya Parrish

[Emma]

You are the best thank you!