The numbers that are used to calculate load average are tasks in the run or uninterruptable state and the amount of work done in the time slice of the moving average. These tasks can be part of a multithreaded process. The fields are fuzzy the farther back in time due to smoothing results from the algorithm used.
A load of 1 is equal to 100% of one CPUs worth of work. If you had a multithreaded application that managed to have a number of active threads in excess of the number of available CPUs, then you could have a single process drive the load above 1. This would likely be a short term spike and not reflected in the longer time slice views of the load average.
Also, since the load average was developed before there were multi-core systems, its important to divide the load numbers by the total available number of cores. If this is a sustained load of 9 on a 4 socket quad core system, then this is a 9 of 16 load and not really a problem.