The questions about that list (which I didn't write, it's from an old thread and was posted by a member at the time named Cornbread, who had put a mention of a level 10 in his list, allowing for the 9.5 of Bogatyr) seem to be revolving around the descriptions of the upper levels:
Expert: Top Level 8: Excellent dynamic parallel form, adjusts weighting of skis according to conditions, can ski 90% of the terrain, in 90% of the conditions, 90% of the time at any resort mountain, struggles in very few areas, can ski at this level on Harder Double Diamonds in less than ideal conditions
Expert: Low Level 9: Skis with high confidence and ability on all but the hardest terrain in all but the most difficult conditions, has high athleticism and conditioning, weaknesses are revealed only in the most extreme terrain and conditions, can ski the most exposed Hardest Double Diamonds in the best conditions
Expert: Solid Level 9: Extremely knowledgeable and skilled on the mountain including back country, very few weaknesses if any, is capable of coaching and guiding anyone, is confident and comfortable in any situation, skis where falling is not an option on the most exposed Hardest Double Diamonds in less than ideal conditions, Skis Anytime, Anything, Anywhere, Any Condition, Any Speed
Elite/Rock Star: Top Level 9/10: Off the chart, a true Ski God/Goddess and world class athlete, Skis Sick Terrain!!! Sick Conditions!!! Sick Speed!!! Sick Style!!!
I think that level 10 was there so we'd have a spot for Bode, McConkey, Ralves, and other assorted gods to be assigned to the level system, preserving the level 9 as attainable for the rest of us. Because, every level description I've come across stops at 9. (This is not getting into the instructor levels, that's another thing entirely and I would hope is geared more towards the teaching aspect of things because if you're unable to teach what you do, you're no good to me, even if you're nice to watch. It's another topic.)
If you read @Cornbread
's description, this was his aggregation of descriptions he'd found of various levels, plus discussions here at Epic. I know I'm always bookmarking those sites myself, somehow hoping I'll find something that exactly describes me, but I always seem to fall into the gap between 7 and 8, even using the Cornbread descriptions, which are more like 20 levels (I didn't count them!). And, of course, if someone claims a level, I might look it up.... Especially if they are claiming a 9.5. Lol!
The original thread was ten years back: http://www.epicski.com/t/49569/refined-skier-ability-level-descriptions/0_10#post_627445