Well, physically traveling to a school with higher grade levels is not possible in our district. There are just too many liability and logistic issues. However, there are other options. For example, the district can hire part time teachers to travel to the school to teach once a week while the student work independently the other four days. There could be a resource teacher at the home school just to address occasional computer or work space issues. There is also the online option. However, be aware of state laws and district rules/policies. For example, while lots of mathy kids in my state use AOPS courses, they cannot be used to satisfy credit requirements at the secondary level (grades 6-12) due to strict laws governing online providers in addition to the "certification" hurdle.
AoPS has acreditation from a Western Schools group I forget which now and it is one of its appeals to us. I am surprised to hear that your school is unaware of this.
