I don’t like OC cards. I don’t like holo scratches. I don’t like things detracting from my view of the front of the card taking in the art. Keep all the issues you can to the back. I honestly get more personal enjoyment from a PSA 6 Masaki that has a unnoticeable corner crease than a PSA 10 that is at the borderline of OC-ness allowable.
I mostly collect well centered clean holo 9’s because 99% of what I have in my collection is a 9 due to 2-4 white spots on the back that I never see nor detracts at all from my enjoyment.
For me, a 9’s a 9.
I can take minor flaws as long as it doesn’t distract from the over aesthetics of the card.
Noticeable holo scratches or silvering would probably be the two biggest distractions though.
I don’t like when cards that have obvious post-factory damage get 9’s. If a card had a rough cut out of the pack, has print lines, or is OC that’s understandable but I refuse to acknowledge a card having scuffs on the surface or excessive chipping as a result of handling as being “mint”. I think cards in this category really deserve that dreaded 8.5.
I get centering is a factory issue and the other three are damage but I hate off centered cards. Centering is the thing you see before anything else, it’s the main eye appeal factor, if a card is noticeably off center I don’t care if everything else is perfect I’m not interested.
On topic: If it doesn’t get a 10 because it’s a 60/40 thing, I think it’s fine. Whitening bothers me somehow, I have a perfect PSA 10 with a little bit of whitening on the back which I noticed instantly on arrival. Probably wouldn’t mind on a 9 though, but again only to a certain degree. Edge wear is the least problematic I think, it distracts the least from the overall appeal of a card. Holo scratches are a no-go though, if I notice them.
It doesn’t matter to me too much what the flaw is as long as the front of the card looks nice. Back side doesn’t matter too much to me (when it comes to front being slightly oc it’s not an issue for me as well)