9th graders are mentally 5 year olds

I deadass had to have a conversation with my boss about how a freshman cut another students hair with scissors in my hour. Parents are pissed and I'm standing here wondering how I'm going survive next year teaching only 9th grade...

Context: I just finished a lesson about the Cuban Missile Crisis and I was helping a group and a student who is chronically absent or failing let another student cut their hair as I have supplies for students available and HAVENT had a problem yet this whole year. Mom comes into the office and is mad saying her daughter is the victim and I'm sitting here in the hot seat.

Like I don't know what I'm doing wrong, I try to have my Freshman have resources to be successful but here we are.... please tell me it's not just me