First of all teachers do not have any latitude anymore when it comes to discipline, the discipline is strictly outlined by school boards and administrations. When I was a kid a teacher would smack you across the face and my father would tell me I deserved it. Today the teacher would be fired and there would be lawyers swarming all over the school.
Should the boy have been tasered by police...ONLY, if it was determined by the officers on the scene that it was the best or only way to assure they could disarm him without HURTING him. Subdueing and out of control 8yr old with a weapon is easy for a well conditioned man, however, its not easy to assure you dont hurt him in the process. I dont know I wasnt there and I dont have all the facts.