Your post is often repeated based on the overall number of cases involved.  That is misleading.
The ninth circuit has far more case than any other other circuit courts.  It has only some of its decisions that go to appeal; not all of their decision.  It simply math: a court with 1,000 case compared to other courts with 500 case.  If 1 of 500 case is appealed the court with 1,000 case would have twice as many appeals at the court with 500.  

https://hotair.com/archives/2017/02/10/does-the-9th-circuit-really-have-an-80-reversal-rate/