Hey I am fairly new to homeschooling too, but I have watched my sister homeschool her five children and have picked up a few ideas
from her. You can homeschool various ages. She has done it. Most of your effort will need to go to the 9th graders since you don't
have them for very much longer. You will need to fill in the gaps, if there are any, from being in the public school, but as my sister says
don't stress! You will fit it all in. You have a ton of time with your second grader. I am not saying that you shouldn't spend time teaching
her. I am just assuring you that it will all work out. I don't know how you feel about religious curriculam, but Abeka DVD homeschool is
excellent and you won't have to set everything up. They do it all. And if you get on a certain package, they will even grade it for you.
It is pricey, but the education your kids will get is wonderful and there won't be any gaps in learning. My sisters kids have all done Abeka
grammar and her ninth grader is better than me at it (and I'm a writer)! If you don't want to do Abeka there are a lot of other one out there.
If you need more I can reply with more ideas. Good luck and don't loose heart. You can do this! (PS I can't find the spell check on this thing, so
excuse any errors).