Your daughter has the right to dance - and how wonderful that she does.
She shouldn’t have to treat what others find ‘annoying’ as a reference point.
Her friend assaulted her - now, that is a problem, as is the fact that her friend refuses to take responsibility for her actions.
9 is about the age when female children are bullied into being ‘good’ little girls, who conform to societal expectations. Behave, be a pleaser, put others’ needs and wants first.
In other words - stop dancing (literally and metaphorically).
Teachers and parents should not be referring to any child as ‘annoying’ - certainly not within earshot of other children. It’s bullying and deeply inappropriate.
Your daughter called her friend ‘ugly’, but it sounds like something a desperate child would say in response to having been hurt, physically and emotionally. And you did hold her accountable, so you are clearly teaching her respect for others.
I think too many people in this world ‘walk normal’ because they’re afraid to dance.
So, no - your daughter did not ‘deserve’ to be thrown to the floor. No one does. We live in a world that tolerates (and normalises) violence towards women, so it’s really important that she understands that she wasn’t at fault, and that what her friend did was wrong.
Texting her friend’s mother might be a good idea, just to clear the air. This could be done gently, and on the premise of the well-being of both girls.
You’re a great mum.
May your daughter dance forever.