Your eighth grade grades will not count in college admissions. Some colleges only look at grades from 10th and 11th grade; others look at grades from 9th to 11th grade. However, no college will look at your eighth grade grades.
You’re doing fine; your extracurriculars look great. I think the main thing, as many others have stressed, is to raise your SAT score. It should be possible.
I won’t pretend to know anything about IB programs because I don’t (one of my friends from Florida is part of an IB program similar to @stantonstudent’s, but I don’t really think there are many IB programs where I live, in the Bay Area). However, I’m assuming IB courses are similar to AP courses, in which case, have taking lots of them.
With standardized tests, it could be timing problems that are lowering your scores; I got a relatively high score on the PSAT (216) this year, but I’m used to working within a time limit on tests (that I have the strange compulsion to always be the first one to finish a test helps too). As in, when I take practice SATs, I have almost half the time left over on some sections. Try working within time limits shorter than the ones on the SAT so on the test day, you’ll have time left over. Don’t second-guess yourself. And try not to make silly mistakes on the math sections (I could have gotten an 80 in math T^T).
If your scores don’t improve, you can always look at score-optional colleges; there are some very good ones out there.
Also, y’all should join the Class of 2017 forum 