A setback for Google against Oracle

"Why? This wasn't a ruling of the Ninth Circuit. this was a ruling of the Federal Circuit."

That's true, and it's true that the Federal Circuit's patent rulings bind the entire country. In other matters though, the Federal Circuit has to make a "choice of law" decision, which can include applying the laws of a particular circuit and having the decision only apply to that circuit.

Quoting from the ruling:

"'When the questions on appeal involve law and precedent on subjects not exclusively assigned to the Federal Circuit, the court applies the law which would be applied by the regional circuit.' Atari Games Corp. v. Nintendo of Am., Inc., 897 F.2d 1572, 1575 (Fed. Cir. 1990). Copyright
issues are not exclusively assigned to the Federal Circuit. See 28 U.S.C. § 1295. The parties agree that Ninth Circuit law applies" (page 15).