In order for the Vatican Bank to possess sovereign immunity, they must come into court with "clean hands" and the 9th Circuit should have ruled that the "wrongdoer should not escape justice by invoking the shield of sovereign immunity."
Due to the Commercial Activity Exception clause of 28 USC 1603 the case should not have been dismissed!
See for example Keller v Central Bank of Nigeria, [citing Republic of Argentina v. Weltover, Inc., 504 U.S. 607, 614, 112 S.Ct. 2160, 119 L.Ed.2d 394 (1992)]; Chuidian v. Philippine Nat'l Bank, 912 F.2d 1095, 1106-07 (9th Cir.1990).

According to Prof. Hannibal Travis: "Initially, U.S. courts dismissed claims by Holocaust survivors on the grounds that international law only gave rise to claims between states and was not self-executing in the absence of implementing legislation in Congress. This erroneous interpretation of §1350 was corrected within a few years, and since 1980, the U.S. federal courts have exercised universal jurisdiction in a nearly unbroken line of cases involving offenses properly alleged to have been committed elsewhere in violation of international law."
It seems to me that the case, [Alperin v. Vatican Bank] should have been brought by or appealed to the US Supreme Court by the World Jewish Congress (as an intervenor) as a violation of the Laws of Warfare - E.g. Genocide, Looting, Plunder or Pillage and like offenses prohibited by the Geneva & Hague Conventions! See for example Customary International Humanitarian Law - Practice Relating to Rule 52. Pillage