I teach quilting for my home school group. You will have lots of fun but it is a lot of work too, the kind that makes you feel good at the end of the day :-) 10 girls at once might be a bit much even with helpers. Do your helpers know how to sew/quilt? If not they tend not to be much help at least this has been my experience. My helpers offer to help so they can learn too, haha. If you have all older girls 13 and up then 10 I think would be okay but the younger ones tend to need lots of one on one help.
9-5 is a long day for an 8 year old they will want food and plenty of get up and run around time. I think you are wise not to let any of them cut with rotary cutter but if you change your mind there are gloves you can get to protect their hands. Even we adults have our battle scars from messing with the cutter :-) The accuquilt will save you lots of time with class prep so you are good there. I would suggest that you start with a few small projects to see where everyone's levels are at and so you can try to get them all on the same page. I think you will have a great time with the girls.
I have my lesson plans I am happy to share with you if you want. Mine cover a semester and classes are only an hour long so you will have to adjust them for a full day but you will get the gist of them I think. :-)