Laws are different in other states and Ms. Norton is not licensed to practice law in this state.
The Education Code sections you mention specify the reason for an expulsion from school. Your sons actions fall well with the parameters of either statute.
PC 243.6 is battery against a school employee and can be a serious charge if there was physical injury. A battery is simply an offensive touching. The bruising may or may not be seen as a serious injury.
As the consequences facing your son are serious you should retain a CA attorney specializing in criminal law with some knowledge of the Education Code.