It may not be realistic to double up math the usual way other then geometry and algebra 2 (where the opportunity has passed), since precalculus has algebra 2 as a prerequisite.
If the courses are online self-paced courses, it may be possible to sequentially double up by going through algebra 2 more quickly to finish in a semester, then go through precalculus more quickly to finish it the following semester. But that depends on the online courses being self-paced, and the student willing to take them at faster pace.
In any case, calculus while in high school is not required by most colleges and universities, who presumably understand that some students are not able to take it due to math placement decisions made in middle school (but students who are on track to take calculus but opt not to may be more at a disadvantage).