You use 680.10 (18" for RNC) but that is not usually a burden since the pool light(s) will usually be the only equipment that is required to be wired inside the 5' zone. This will be >18" deep where it goes into the pool wall so it is not really that hard to keep it 18" for 5 feet. Once you get outside the zone you can ease it up to 12". Since you are pulling a #8 and a SJOW cord you don't want many bends anyway. I don't know any AHJs who think "Where space limitations prevent wiring from being routed a distance 1.5 m (5 ft) or more from the pool ..." refers to anything but wiring supplying pool equipment.
