I watched the interview and didn't catch where he said he shifted at 9000+. That seems a little high in Stock, but maybe.... or in high gear only? Or maybe you are you thinking of the recent Ray Paquet interview possibly? He runs in super stock, completely different combo even though they are both 427 high risers, I think he mentioned he turns it 9300 ish in his interview video posted while back.
For most guys, as bracket racers or hot rodders, ultra high RPM is not warranted, longevity and repeatability is. For class racers with strict rules, more RPM equals more power, so they go as high as they can stand, and at a severe cost I might add. Both in expensive parts and short duty cycle, with possible carnage along the way.
Too many variables as others have said, build to the best you can afford, put a number on it and don't turn it above that RPM, or at least not very often. I turned my old 428 only 6500 and did it for years and years, no problems, hundreds of passes if not 1000. I turn my old center oiler with a forged 4.25 crank 7000 on the shifts and on a good run 7300 through the traps. Pistons aren't real lightweight and neither are the rods. I plan on building another high riser with much lighter pistons and rods, and a shorter stroke 4.125 that has been lightened as well, in an aftermarket block, will turn it higher, how much higher I don't yet...