I had to chuckle! My reply was: "Eleventh grade, if you're lucky" :-)
Truly, take heart. I'm sure others have more boys they are schooling at home, but as the mother of three sons (and one daughter, God bless her!)....I do have something to say about it.
I think some of the harder grades for getting boys more interested/involved in their school studies is from third through 7th grade. Those levels can be tough for active boys. I can't believe we've gotten as far as we have [with my 8 year old - third grader], as I have to pin him down constantly to stick to his work. He's a pirate, he's a warrior, he's a knight...he's a robot maker, he's a comic strip writer, he's Calvin with Hobbes :-)....he's a pain
However .....press him, I must into every bit of school I can squeeze out of him. He loves science and has moved quickly through the science text, and I've diverted him out of it on a couple occasions to read some rabbit-trail materials covering certain science-related topics he's been learning about; i.e., I found a couple neat books on our shelf (from an old Catholic school library closing - the one my husband attended), and they were: "Bufo: The Story of a Toad", written and illustrated by Robert M McClung (who wrote some great nature books, accurate, illustrated, for young people), and "Tiger: The Story of a Swallowtail Butterfly", by the same author. (these are 1953/54 copyrights, library editions 1970). He did find these interesting and it helped to keep him in the school mode. It's like sneaking in the school when they're not looking :-)
Boys. It's probably good my three are spaced out some. Or maybe it's just that I'm spaced out and it sounds better.
Space Avenger for 3 sons, 1 daughter and 1 ransomed sofa pillow :-)