I'm going to take a slightly different tack here, but not meaning any offense. This is certainly a gray area.
Yes, the standard recommendation is 30 days for wheeled cleaners, mostly because they can spin in place, which can be pretty aggravating to any non-cured surface. But as far as damage from feet? Your pool finish sat in the open air for two days before being filled. Pebble is basically a concrete type product. I would have zero issue gently going in, and for me, so long as I wasn't jumping, gouging and my toenails were trimmed, I wouldn't be concerned on pebble. If I wanted to be super cautious, I'd where Crocks.
In one of the threads above, a PB member says he lets his clients go in as soon as the water is in and being filtered (obviously assumes no hot acid start), and he sees/saw no damage from it. And he would be on the hook. But agreed, that PB's may not always be the best for such advice.
These are just my thoughts mostly, so don't do it because I said so. It needs to make sense to you and you need to be comfortable with any problem you create that was contrary to advice from your PB.