I don't know about 9-year-olds, but in my DS's high school, this kind of behavior is strongly discouraged by the school. It is simply not nice, and adds pressure to other kids. If this happened at my kids' schools, I would talk with the teachers first and get a sense of how they feel about it.
I agree. It sounds like a class culture issue. If the teacher is fine with it there is probably nothing you can do but if the teacher doesn't like it or simply hasn't thought about it then a few simple expectations should help. When i was at university we never discussed grades but they were listed by student number so you could see how you were doing without knowing who got ehich marks.
