What are suggestions for keeping a 2nd grader from walking around classroom and interrupting teacher nonstop throughout the day?

Our student does not respect personal space or boundaries. He refuses to stay in his desk space/area. He constantly runs back and forth in the classroom or walks around the room nonstop and stands by the teacher and interrupts her when she's providing instruction. He takes items that are not his. He refuses to attempt academic tasks though has demonstrated he can do them quite easily. He acts like a cat, meowing and scratching peers and teachers. He complains that kids don't let him play at recess. He elopes or will cry loudly in the room if even small things do not go his way. The teacher has a token economy system in place. He has big emotion when he loses a token and that disrupts the learning environment for extended periods of time as well. The classroom also has a restroom inside of it and he locks himself in there for up to 15 minutes at a time 2-3 times a day. He avoids academic tasks and has several refusals throughout the day. Help!