each state is different in what they allow.

In OH if they do a high school course in 7th or 8th grade it will count towards high school credit but it has to fall into specific guidelines.

When we enrolled them in school though ds was going into 9th grade and the only credit they allowed to come forward was math, everything else he had to repeat.

Dd had almost all of her credits accepted as she was going into 11th grade. Many of them were done at the 7th and 8th grade levels.

Each state and even each school district is different on what they accept or decline.