I think you need to go to this meeting clearly stating that her taking all three of these subjects are NECESSARY for her or routine & normal for a 9th graders. Like NotSoGifted say, Algebra II in 8th grade is taken by about 10% of our school. Go in explaining that you aren't just trying to meet H.S. requirements, but those for most 4 year universities.

1) Math -- Algebra II is a necessary course for her to take this year. Your H.S. must expect at least 2 years of math, and mine doesn't allow you to skip math until you have at least met minimum requirements. She has already passed Algebra & Geometry what do they want her to do, skip math for the year?

2) Spanish (or another language) -- is necessary since any top tier university will expect at least 3 years of a foreign language. Some universities only require 2.. but most want to see more. This is not really an elective IMO.

3) Band -- because she needs this for social/emotional. Being involved in the school, and participating in music is very important. And universities do look for this type of participation.

Ask them how they are going to make it happen. It sounds from your initial post its (Spanish & Band) OR ALgebra II right? It doesn't sound like the course load is unusual at your school (my son took all 3 this past year and he wasn't alone in doing so), nor something your daughter couldn't handle just that someone messed up with the scheduling so this wasn't possible. Someone who was setting up scheduling should have made sure that this was possible, your kid can't be the only one wanting to take Algebra II & 1st year Spanish. I find it very helpful in this kind of meeting to first make it THEIR problem and see them struggle with how to solve it. And THEN suggest your and your daughter solution, the independent study suggestion.

Bring you daughter to the meeting if she already isn't going to be there. At my H.S. the students are always excepted at this kind of meeting. Since you say this is your daughters idea, I would think it would carry more weight. If she can make the presentation to the adults it will be a lot more convincing than you presenting the idea.

Good Luck.