I'm sure you'll get more concrete answers from others on the board who have kids in school, but I know that finding a teacher who "gets" your kid helps immensely.
I would ask what sort of options do they have for kids who are working above level, e.g., differentiation (and if yes, ask specifically what their idea of it is), various acceleration options, going to reading groups with older kids, going to higher math class, grouping.
Ask if the teacher has any specific experience with gifted kids, and what it was.
Don't use the word "bored." Try to work around this by pointing out what levels your child is working at. You don't want to offend teach straight off.
Be prepared by knowing some options you want your DS to have.
Just random thoughts. Others will have more experience.
