The issues with not currently being in the military and therefore a letter from your commanding officer regarding your prior handgun training aside, there's more to the handgun safety course than familiarity with the safe handling and operation of firearms. The HRS requirement also includes instruction to become familiar with the State of Hawaii laws regarding legality of specific firearms, transportation requirements, use of deadly force, etc. The course also covers safe handling of various types of handguns, like revolvers, and goes beyond the experience that even someone who possesses a mastery of the M9 would have.
Just some things to keep in mind. Not saying that your frustration isn't warranted, just saying that there are other things to consider. In the end, there are specific laws in effect and just have to live by them until they are changed.