A mature student can self start and do great. Though in my experience, even talented young people need guidance. This is why I recommend the books. Artistic Pursuits is my favorite choice when you don't have a teacher. I have seen used copies at homeschool classifieds website. Any technique book that is written in an engaging way will give someone guidance. As a parent, you will have to help her schedule a specific time and days to work. Without a plan, or a teacher - it can be hard to know where to start. As the parent, you can help her with planning a specific time, think of it as scheduling practice time for a musical instrument - this time it is just another fine art. When resources are limited - like time or money- as the parent, you can still help growth happen by helping your daughter plan. I do like the point of the reply above, keep media interest in mind. It is wise.
Another option is to check your local art museum school. Many of these museums have classes for young people in various media such as drawing, clay, jewelry making, stained glass, painting, etc. In my town, the classes are cheaper than having a private teacher. I have not checked the school house magazine website with all of their classes. Homeschool Buyers coop has lots of art stuff all the time. The more you look, the more options you will come up with. Craft stores like Michaels, JoAnnes, Hobby Lobby offer various short term classes that might be a good jump start for getting going in a direction of independent study. A class designed for adults might make an exception and let an interested high school student in. When I was in college, I taught art lessons to local homeschool children. If you have a university in your town, you might be able to call their art department, and make some contacts for possible college age tutors. Bob Jones Press has an out of print high school art book from Kathy Bell. I have seen it on the CBC website as well. I have a few copies of it. While there are things about it that it that I like, the book is written with the assumption that the student has prior art history knowledge. I will look on my studio shelf and see if, there is anything else that I have that might be an option worth considering as you research.
Since your daughter in a rising 9th grader, whatever art time she does can count toward an elective credit - depending on your state laws. So, she can do a 1/2 credit of art 1 with whatever book or path you choose.
Oh, your local museum might also be doing a highschool art camp - this next summer. Some universities offer these for high school students too.