Firstly each player has to be rated in comparison to each other player, you cant say player X is a 9999 just cos he is a current England international.
Secondly when I watch international player X ( 7 knowledge ) play he always does the same things, but when I watch international player Y ( 9 knowledge ) he has the capability to do the unexpected. A 7 knowledge skill is the standard for a top international like player X, worth a lot more than a 6, but player Y is worth more, so he would be rated at 8 or 9.
A 9 knowledge skill gives player Y the chance to do certain actions I haven't even finished coding yet because I'm still learning from watching him and then coding these real life actions into the game. Whereas player X only seems to do actions that are already coded and have been coded for a long time. So that really is the difference, it's what I see when I watch the players.
Just out of interest I have recently retired about 200,000 lines of legacy coding that the current crop of international players just don't do anymore. Coding that applied to players like Bergkamp, Ian Wright, Gary Lineker, Kinkladze, Gazza and the like. If somebody new comes along in the future that emulates these truly great players I can bring it back.
This was a reply to a private message I thought was worth bringing into the open forum.