If your goal is to get a PHD from an Ivy+, your best bet is to attend a feeder LAC (Check “colleges where PHDs got their start”) or another Ivy+ (less efficient path to PHD but more famous). Though at this point I’m guessing you’re using “PHD” as a form of signaling. Which is fine for a 9th grader 
Do know that intellectual cross pollination means grad programs prefer their grad students not to be former undergrads.
You will need to build your college list from the bottom up. Everyone can say they want to attend Harvard- zero originality 
, everyone and their grandma knows that college, but that’s no proof it’s the right fit for you. Maybe it’ll be, maybe it won’t. That’s not where you start.
Finding affordable safeties you like is always difficult.
You’ll need to know your parents’ budget and it may well be you wouldn’t be able to afford an Ivy+. You may have to hunt for merit (NMF ie., the PSAT October Jr year, would matter a lot). You are really lucky because you’re living in California, home to incredible public universities and a full system for everyone.
You can start visiting whatever colleges are nearby - a CSU, a UC, one of the Claremonts, a small private college like St Mary’s or Oxy, a midsize one like SCU or Chapman - NOT because you plan to attend but to see what the campus feels like, what you like and dislike, and broaden your list.
Most importantly, college adcoms at elite institutions can smell a student who did things just for college, to match someone else’s idea of who they are. So, do what you like and do it well. Be yourself. Be kind. Have fun.