Homeschooling is a big adventure, even when you start getting into middle school. The time is still pretty intensive, though at this point your junior high school student should be able to homeschool themselves. They are going to need direction, input, advice, and guidance - yet on a regular basis they should be able to homeschool independently.
There are great resources available to the homeschooling family. Resources that include videos, online courses, teacher directed online courses, co-op courses, and even great literature based studies.
Here are some great resources for eighth grade learning
Eighth grade math worksheets