Zidane, Cruyff, Platini, Maradona, Pele are one of the most synonymous names in football. You just can't really put those above CR. Nothing really suggest they're better or more great than CR is. Of course, it's an opinion but there needs to be something else than opinion included or otherwise you could name anybody. Titles, Stats, Longevity, Influence, Era's etc. needs to be taken into the account.
With R9 it will always be if, could, should and would = did not happen. There's actually quite many players like that in different sports, but there's always reasons why it never happened. That speculation is unecessary, because it simply never happened.
Yashin vs Buffon, so you based your experience on for what you have seen, so it's not really a real way to put it. Or is this Youtube as an experience about the player? Can you really build a proper image about the player from the google etc.? I would never even go so far, that i would even try to judge the players i'v never seen, neither even bringing to GOAT discussion because it will always be more like someone else's opinion than yours. It will always be based on stats, very limited footage and words from the co-players.