It certainly looks like Carp Pox to me. There is a lot of information on the web about Carp Pox...I suggest you read up on it as much as possible and get specialist advice, but there are a couple of basic facts (only what I've read myself) about it...
It will spread rapidly in crowded ponds.
It is not generally life threatening to otherwise healthy larger fish.
It is however, devastating to young fry.
Warm weather seems to help in lessening the effects.
Large Koi (15 inches and above) have by then developed a good enough immune system to avoid Carp Pox symptoms, although if they have ever had it, they will carry the virus for life.
The visible signs usually disappear over time.
There is no treatment...although there are some so called cures on the market, non will work.
DO NOT try to remove the waxy spots yourself, as infection will get in to the affected area and you will lose the fish.
I'd also suggest you take the photos and a sample of the pond water to an aquatic specialist and get it analysed...even though its a big enough pond and there is filtration set up, Koi are such specialist and sensitive fish they are a mare to keep. Even a small fluctuation in temperature or water quality will stress them out and reduce their immune system to the point where infections and viruses can spread throughout them very quickly. A water sample may point to an area that can be improved if nothing else.