If the Prop 8 opponents lose this round, will it then go to the 9th Circus Court - er, Circuit Court?
I’m not a lawyer, but this is a state issue. The 9th Circus is a federal court, so no, I don’t believe so.
"Show me just what Mohammed brought that was new, and there you will find things only evil and inhuman, such as his command to spread by the sword the faith he preached." - Manuel II Palelologus
A federal court would not have any jurisdiction over a CA Supreme Court decision. The issue involved is a matter of the CA constitution, over which the CA Supreme Court is the final arbiter.
The Prop 8 opponents might try to go through the Federal courts (they'd have to go through a lower level court first, before being able to appeal to the 9th), but they'd face an impossible task.
The California Supreme Court has the final say on how to interpret California's laws. It becomes a Federal matter only if there are issues that are in conflict with Federal law or the US Constitution. For example, if there were a provision based on race discrimination that was upheld by the CA Supreme Court, that would raise Federal issues under the 14th Amendment. If the provision in question were based on gender, it would be trickier, since we don't have a Federal ERA, but there are Federal laws that make gender a protected class. There is no decision that makes homosexuality a protected class, just Lawrence v. Texas, which merely prohibits a state from sanctioning private behavior.
Expect the Prop 8 opponents to try based on that case, but expect that even the 9th will have nothing to hang a decision to void Prop 8 with. And if they do, even Tony Kennedy will slap them down for it.