Three of my four children were home schooled through junior high and I think it was a very good thing. Junior high is a very difficult time for most children. They are hitting puberty and have all sorts of confused feelings. They usually feel awkward and don't really know how they fit into society. If you ask most men when they were first introduced to pornography, it was usually in junior high.
My home schooling was very simple~
I chose good books to read, non-fiction and mostly historical fiction. They would spend several hours every day reading. This helped them to develop a love for reading. They are all good readers now and enjoy reading. It helped develop their vocabulary and their imaginations.
I also had them memorize Scripture. Memorizing helped develop and strengthen their brain power.
They would also spend an hour or so every day doing math problems. They are all very good at math so this was easy and I LOVE math.
Then they would play and exercise their bodies. I took the boys to the beach to surf a lot. They were both heavily involved in team sports. Alyssa took ballet almost every day and Cassi took ballet and played basketball and soccer.
After junior high, we enrolled them into the nearby Christian high school. We had no idea how they would do since they had really only read books and did math in junior high, but they all did great!
I think if your children are good readers, they will do well in any subject. Most children don't read that well. The books they are given in school are boring. So pick out great books for them to read and develop in them a love of reading. I think this is the key to having good students.
Also, let them play outside a lot! It develops their brain and their motor skills...vestibular (balance), eye movement, hand-eye coordination, sensory stimuli, knowing where they are in space, vision, and hearing. Don't let them watch much television or be on the computer much when they are young. You can find a lot of good information about this at: Brain Highways.
...that they may learn to fear me all the days that they shall live upon the earth, and that the may teach their children.
And they shall teach them diligently unto their children, and shall talk of them when they sit in their house, and when they walk by the way, and when they lie down, and when they rise up.