I would normally say that his best bet is to fight the bully. I did that in elementary school and got them to leave me alone. Not only that, but when I gave a bully 4 years older than myself a black eye, he tried to become my friend. Zero tolerance kind of puts a damper on fighting, but it would still probably be worth it in most cases.

However, the way you have described this kid, he seems dangerous. Threatening people with scissors is not normal behavior, so your kid could very well get hurt. You should work your way up the chain of command in the school system. Never make threats: "I'm going to get you fired," "You're going to get a call from my lawyer," or "This will make the 5 o'clock news" are not going to get you meaningful results. Instead, it is better if you go into any meeting with two people. One person plays the nice guy routine, while the other plays the mean guy routine (without making threats). If they prove to be uncooperative, the nice guy can play the really-mean guy routine, still not making threats, until they back down a little. If you still haven't gotten any results, go up one level to their boss. Rinse, repeat, until you have gotten as high as you can go. Only then should you consider outside action (TV, etc.).

Another advantage of having two people is that you can have one person watch their facial expressions and reactions while the other is conversing. This gives you an enormous advantage. If a tactic isn't working, the other person can get around the impasse. If they try to back down from something said earlier, you have two people to call them on it. You are going to be severely disadvantaged if only one person goes into the meeting.

If you make threats, you are only going to make them want the problem to go away, probably by passing it on to somebody else. You do NOT want them to just keep passing the buck around! If they finally were to give in from threats, which is unlikely without a LOT of pressure, you would be a pariah in your town and your kid would be ostracized at school. Try it the easy way first.

Note: There are also strategies you can use in conversations. Mirroring (imitating someone's stance, etc.) often helps to develop a quick rapport. If they cross their legs, cross your legs. Another simple tactic is repeating what they said. "So what you are saying is, I should rephrase whatever they said?" There are hundreds of other tactics like this. They work, and work well, as long as they aren't too obvious or used too much. If you aren't comfortable doing them, keep it to a minimum.

-Biscuits