Earlier quoted context omitted.
What kind of kindergarten expels children? It sounds at best grossly incompetent. Are you sure there was no other bias that played a role in their decision? It sounds rather unlikely you were the cause.
When they start having to spend 80% of their attention on one kid, it's a problem that needs to be addressed. I say this as the parent of a kid who is right on the verge of being kicked out of preschool over that issue. I totally get it. I wish I knew how to help him. He has some great qualities, but he also requires constant attention and mentally draining correction from everyone that's involved in his life.
One of the Montessori practices I'm a big fan of is observation. Quiet almost secret observation of the child. Ideally the child isn't aware you're there and you merely observe them act freely (in a safe environment for the child).