Hi Chris,
Not sure if I understand your question properly.
Simply gaining insurance will not make you an "endorsed IKO Instructor". IKO are not able to supply an insurance policy to cover you teaching people to kitesurf or anything else for that matter last I heard.
What you need is public and property liability insurance to cover you from incidences with the public and the public's property.
You also need professional indemnity insurance for wrongful information, ie, if the info you gave to a customer leads them to harm. For example, you tell them the conditions are ok to teach and they trust you and launch a kite, then they get lofted or splatted into an object due to a weather anomoly and cause a claim, then you are covered. Liability Waivers do not hold any worth in the Australian legal system. You cannot waive your liability.
I don't know of anyone offering specific instructor insurance that would be affordable for an individual. There are a couple of companies that offer Kiteschool PL insurance, but if it is just you, then you would work full time for 3 months just to cover the insurance premium. Not even close to commercially viable for an individual.
If you want to be covered by an insurance policy, then work for a school that will cover you with a proper valid and up-to-date insurance policy and find out what will void the insurance. If the school has insurance but no legitimate council permits, then their insurance is worthless as the insurance investigator would deem the policy void due to trading without legal permits.
If insurance is a concern to you, you should do your homework. You could find a easy few extra dollars will cost you a lifetime of debt and hardship

DM