I encourage you, if possible, to change your perspective a little. As matter of fact, it is about going to a top or selective university four years later. I suggest you to search some of excellent days schools which have the same or better record of sending its graduates to top universities. You can have some advantages even when you transfer one year later from this top day school to a top boarding school because top schools recognize other top schools' reputation and academic curriculum, and often welcome the accomplished students at other top tier schools. Start your study somewhere, complete your course there or prepare the transfer next year, but please definitely be in an environment that helps you be more competive for admission in USA, if you plan to go to a selective university later.
It is so sad that an excellent candidate such as you did not get any offer. I am constantly hearing from top boarding schools that there are simply too many Chinese students this year, and top boarding schools are having such a hard time to pick students. Imagine that more than 200 applicants for four spots that are allocated for Chinese students. It is apparent that even students from big cities such as Beijing and Shanghai are competing with other outstanding Chinese students from other areas. Also it seems that postponing one year would not help much either. All outstanding international students who are currently at junior boarding schools such as Cardigan Mountain and Fay or other top private schools who are already in USA will apply as the 10th grade next year to the schools who would offer fewer space for 10th grade.