See bit.ly/2OWTc3R ...
... the reversal rate for all courts in the Supreme Court last year was 74%. All these statistics tell us is that one major factor in the Supreme Court’s selection of which cases to review is whether they may have been wrongly decided: 
The number of Ninth Circuit cases reviewed and reversed was high, but the Ninth Circuit is by far largest federal circuit by number of judges and size of docket.
Anyway, to put the point more simply, the Supreme Court doesn’t usually take cases to affirm them, which is why the statistic the President is citing is misleading.
As @adamliptak wrote in yesterday’s New York Times, the Ninth Circuit covers “a fifth of the nation’s population and a third of its land, in nine states and two territories”—hence the huge docket.
