There is already binding Supreme Court precedent that explicitly says that the US Constitution does not provide a right to same-sex marriage (Baker v. Nelson). Even the 9th circuit wouldn't be crazy enough to completely ignore directly relevant precedent. The 9th circuit has reached a lot of crazy results, but I don't think even they are loony enough to reject direct SCOTUS precedent and invent a right to gay marriage. And even if they did, I'm confident that the SCOTUS would smack that idea down.
Not if Obama plants a couple more liberals on the court. The Democrats can create two new seats and they wouldn’t even need Kennedy to vote with them.