I think you have the best possible chance of getting into a top tier grad school in the US. That said, top schools are never a sure thing! I don't think anyone can give you a percent chance. But you should confidently apply to every program that interests you!!
As for safe schools, I would avoid public universities especially in California because they have a VERY LOW international student rate. I think the whole University of California system has an average of 10% international student population. For example, UC Berkeley accept < 10 people per year in astrophysics, so in my field, you really have to be the best international applicant in the last 1-2 years to get in! The numbers might be slightly better in physics? So if the UC schools are one of your top choices, then definitely go for it, but I wouldn't count on it as a safety school. Unfortunately, this is true for most California schools and their private schools are also top tier. However, my profs who worked in the US system say that the east coast is much better for international admittance. I don't know what schools would be good though, but hope that's helpful.
And finally, for many international students, our home university is our ultimate safety school. So it's common and good practice for us to only consider US schools that would provide a better opportunity than our home university!