If she’s strong in history I don’t think she needs tutoring or anything of the sort. Mine took AP US History last year and had a little trouble with it initially. Her teacher recommended Shmoop which is this online prep resource for the AP Exams and I think she was much more comfortable with the subject once she started using it. She aced it too (can’t resist mentioning it, just so proud of her!) so your DD might want to try that as well.

Reading fast is a good thing, it means that her brain can interpret symbols easily and can put a meaning to it. Its a gift which only few can get, but she needs to learn to concentrate, so i suggest that you promote her to read repetitively until she finely gets to understand the whole meaning in one reading. I know a girl who is around 15 years old and has such fast reading skills that she read The Lord of The Ring in 5 hours and was easily able to recall events and characters in the novel. It was really baffling, but its not just a gift but a lot of practices of reading faster and faster.

You can not have a universally accepted kind of of expectation from you wards. You must remember that every child is special and its that one particular skill which he/she is unique and excel from everyone. You must explore the opportunities that your ward can take and then may be you will realize your ward.

The gifted always find their way out or they are better off among themselves thus building a better bond for future.

It is never wrong if you DD is excelling and is in such a speedy momentum, just maintain it at that rate, the learning rate of people reduces with age and this is the best time to harness all of it.

Yes for now you can ditch grammar for sure. It won't matter so much, but you have to keep a tab on his spoken English, it may become difficult to teach him grammar later on if he is unable to get off the grammar.