In LAX they have all the a380 LAME's over there who would be able to troubleshoot the problem at least, and get the plane back in the air in a shorter amount of time. In Honolulu you would have to wait for a suitably qualified LAME to get over there and wait for spare parts if required. Keep in mind, the a380 has 21 fuel pumps. Depending on which fuel tanks the pumps failed in, having 2 go in separate fuel tanks isn't a major problem, but you would want to divert to an airport with all the suitable technical support which Honolulu doesn't have for an a380.
Cheers.
Correct me if I'm wrong, I assume 2 pumps inop on one tank would not allow a fuel transfer out of that tank, reducing range (maybe imbalance later on), hence requiring divert?
9.5 hrs only to head back to origin would leave a fair few pax pissed off.