Your son is showing signs of emotional disturbance and he should be evaluated by a pediatric mental health clinician. This situation requires more than home-based behavior management (though that is also important).
The most effective system for a child this age is to base the rewards and punishments on a 24-hour cycle. For example, let's say that a child enjoys a particular television show each afternoon. The way he would 'earn' the opportunity to view that show would be by bringing home a positive report from school. If he did not, he would not be permitted to view the show and he would also receive a 15-minute time out. The system repeats itself each day.
My six year also has problems in school. He has not had full good week since kindergarden last year. We don't know what to do. The teacher says that he is fine in her class, she strict like me n my fiancée, but his Japanese, Spanish, pe, or music, and if there's a sub forget about. They swear he doesn't have any wrong with him...the only thing that "work is spanking him" we don't want to conintue spanking him. He almost burnt down my bathroom... we showed him pictures of burn victims and now he's doesn't do anything with matches anymore. I planted some in his room and he brought them to me