I ran my wheeled vac after about a week, at the advice of the plasterer, no issues. But there is a contingent that says 28 days, so not sure. If it was plaster (no pebble), I wouldn't take the chance. Theoretically, the plaster holding in your pebbles should be "lower" than the pebbles, so the wheels would only touch the pebbles, and the pebbles are tough. The call should be made by whoever would be honoring the warranty. I'd want that instruction to be in an email (paper trail, just in case). Polarises (Polarii?) do have that tail, so that's something to consider, that thing does swing and bang around.
Scrub the heck out of the Polaris, do what you gotta do to get it clean (without compromising the plastic, so use bleach sparingly, if at all), then rinse it well, or give it a bath (submerge it in your bathtub if you're really worried about it, I wouldn't). Humans are going to drag way worse into your pool than a little soap and water...