Experience tells me that option 1 should be faster, because you're making just one call to the compare method and storing the result for reuse. Facts that support this belief are that local variables live on the stack and making a method call involves a lot more work from the stack than just pushing a value onto it. However profiling is the best and safest way to compare two implementations.
The first thing to realise is that the java compiler and JVM together may optimise your code how it wishes to get the job done most efficiently (as long as certain rules are followed). Chances are there is no difference in performance, and chances are also that what is actually executed is not what you think it is. One really important difference however is in debugging: if you put a break point on the return statement for the store-in-variable version, you can see what was returned from the call, otherwise you can't see that in a debugger. Even more handy is when you seemingly uselessly store the value to be returned from the method in a variable, then return it, so you may see what's going to be returned from a method while debugging, otherwise there's no way to see it.