Aloha,
First off, I'll apologize if this has been asked and answered before, but I searched the forum and didn't find anything so here goes.

BACKGROUND: I want to take my children (16 y/o girl and 13 y/o boy) to KHSC to fire my .22 pistol and my M4. (both weapons are registered with HPD, will be transported in locked cases, etc, etc. The children will be in my presence and under my supervision the entire time we're at the range).
My son earned his Rifle Shooting merit badge from the Boy Scouts, which I'm told may satisfy the requirement for a "Hunters Education, NRA firearms safety course, or equivalent training" in firearms safety.
My daughter hasn't had any formal classes in firearms safety.

QUESTION #1: is formal firearms safety course completion a requirement for minors to fire at KHSC?

QUESTION #2: any recommendations on a good basic firearms safety course here on Oahu?

Ultimately, as their father I'm responsible for ensuring they are educated in how to use items safely: whether it's a hammer, knife, stove, bike, car, firearm or anything else. But formal firearms safety instruction is a good idea, IMHO, so I could use more info.

Mahalo!
Ted

No. They just need eyes and ears.

Teach them as much safety as you can.

Any minimum age? Someone told me 12

This is from Koko Head's website (www.khsc.info)

Children age 17 and below must be accompanied by an adult
Children 9-12* years may fire .22 long rifle caliber only, with an adult standing next to and assisting the child
Eye and ear protection mandatory
Children 8 years and younger are prohibited from using firearms
* Youngsters with a valid State of HI Hunter Safety Card may fire centerfire rifles.

You're good to go without any certificates or anything. 

I got rifle, shotgun, and archery merit badges while in Boy Scouts. I don't remember any of them meeting the requirements for safety classes but you do get a NRA certificate of proficiency. If you want them to have a formal safety class then you could sign them up for the handgun safety class through most any local gun store, depending where you sign up I think the cost is currently running $100-250 per attendee. Hunters' Ed is of course free through DLNR but it breezes over firearms and concentrates mostly on safe hunting practices and being a good sportsman.

Terrible Ted...........are you in the military?  If so you can join the Schofield Rod and Gun Club.  The SRGC periodically offers safety classes geared towards youth.

If not, then formal training OGC maybe? 

We teach kids and stuff all the time. I believe OGC has an age requirement, you can check with them; they refer me families and people with kids often.  So far the only requirement has been an ability to hold the firearm above the bench.