We have 13 girls in levels 8-10, ages range from 10-18. Almost all of our girls have had injuries that have kept them out here and there...
My dd, 12 yrs old, lv 8, was out a total of 12 weeks last year for various small injuries
12 year old, lv 9, has been out since April with back issues (she's come back here and there to try to work out)
12 year old, lv 9, has been out 6 weeks with back issues, was out 6 weeks at the beginning of last season with broken thumb
15 year old, lv 9, out 6 weeks with knee injury
13 year old, lv 9, out 12 weeks with broken toe that required surgery.
I think it happens...unfortunately. High level optionals means higher chance of injuries.
I hope I addressed your question.