I looked at my choices for 9th grade classes, and I want to make sure I made a good decision. There was Algebra and Geomotry for math. I chose Algebra honers(now that I think of it, I should have chosen Geomotry Since I don’t know too much on Vectors). As for science, I chosse physics over biology. What’s your opinion on this combination?
9th grade geometry doesn’t teach vectors in my experience, that didn’t really happen until algebra 2/pre-calc. (Pre-calc is usually a waste of time btw, it’s just algebra 2 again)
Physics will will involve vectors though, although maybe not at the 9th grade level as I don’t know your school’s curriculum.
Physics in general is just applied algebra (and calculus later), so you probably made a good choice taking algebra alongside it instead of geometry.
I didn’t see much other classes beside core classes and a few ellectives, but on their website, they have quite a lot.(I CLTRL + F’d and saw some computer programming for 9th grade). Are there classes where you have to sign up for it in school or something?
I’d definitely concentrate on English if I were you.
Cas 
The best advice you can get is from other people at your school who have taken classes you might be interested in. Ask around.
I think it depends on the country you live in but IIRC we did learn about vectors in 9th grade, although nothing serious until 11th grade.
Learning vector math is easy but really helpful, you’ll be able to utilize it a lot even if you have got only the basics down.
Look up the following things online:
- Some general explanation on what vectors are and what are they used for
- Adding, subtracting, multiplying, dividing vectors
- How to create a vector that points from A to B (although the previous point pretty much covers this)
- Vector normalization and why unit length vectors are useful
- The cross and dot products
- How to create a vector from an angle (atan2)
- Optionally look up trigonometric functions since they are really useful too
You can learn all this in 1 or max 2 days and you’ll use this 'til the end of your game development days, you don’t have to wait 2 or more years for school education.
Edit: If you get stuck with any of the points above feel free to ask help here or message me in private, I’ll help you out.
Algebra2/Trig was 9th grade but we didn’t learn vectors until precalc the next year (this may have been because of our 30 year old textbooks ;D)
Since you are going to take Algebra you’ll be inundated with solving systems of equations from the implicit angle where your variables x, y, & z are in the same equation. That is one way to structure equations. There is also the explicit form called parametric equations which provide separate equations for each parameter which achieve the same result as the implicit form except is much easier to manipulate because the one variable usually is (t == time).
Example for a circle…
Implicit form:
x^2 + y^2 = r^2
Explicit / parametric form (t == time):
x = sin(t)
y = cos(t)
Which one do you think is easier to manipulate programmatically?
Want to create a circle moving through a cylindrical motion moving forward in time… Guess what…
z = t
As time moves forward you move in the z-axis making a circle…
Parametric math is extremely helpful for creating patterns, paths, and working with projectiles or particle systems.
The above also defines the unit circle which is something you should internalize along with the unit sphere in terms of rotations and other fun stuff that will be rather handy for 2D and 3D game dev.
I was pissed that in all the math classes I took in high school it wasn’t until I was in a calculus class in college that offhand one exercise set had a few problems doing calculus on parametric equations which were not introduced as something unique; just more problem sets to plug through. I immediately saw the independent variable (t) and saw how it related to all sorts of useful graphics use cases. This could be taught to 9th graders yet for whatever reason unless you have a savvy teacher or good math book that relates to computer graphics concepts most highschool algebra is plugging through exercise sets with implicit / systems of equations busy work.