To begin, it is ok, legally not ethicly, for a youth minister to kick out a kid from group, now, if when you say kick out, you literally mean kick out, in physcial terms, then no, that is not ok, a youth leader is to be trusted with kids, and should never EVER, under any circumstances, touch a child.
We had a kid in our youth group that was rebellious, disruptive, and many thought he was dangerous. He had no problem using foul language and interupting the teaching that was trying to happen. Our youth pastor and pastor met with this kid several times with and without the parents. Finally the parents were told that if he couldn't control himself in youth, then he needed to stay with the parents in church, or at home on youth nights. There is nothing wrong with asking the parents to gain control or stop bringing the kid to youth. When asked why he came, he said only to disrupt and cause problems for his parents. At least that part of him was honest.
Now, here is the question, what is rebellious, does he question things? Does he back talk adults? Does he openly disobey? Rebellious is such a hard word to understand, but I believe if he is a threat to others in the youth group. Which is moat likely very hard to assertain, then he sould be removed, yet the child needs to learn about God some where, and I ask, once removed, where does one go? But anyway, I dont say a church that kicks a kid out is evil, but I do question their spirit of grace, mercy, and love.