You would need an engineer to calculate out the specs for you. Also you would need rebar and a plaster finish as the water will leak right through the concrete blocks and grouting. I don't think many people build this way due to the cost, life span and functionality. If your looking for a cheaper DYI pool - look at what people have done with steel shipping containers. Some pretty cool builds.
You should look at a website forum call Koiphen. It is about ponds not pools but a number of users on that site do huge above-ground cinderblock ponds and you can see the engineering required as well as the designs. You have to cut all of the blocks and rebar every course