When something is publicVariabled, then it is updated on everyone's machine, including the server. When a new client JIPs, then the server will send them the last value that was publicVariabled (i.e. the value is synchronised on JIP).
You can't make a variable with the player's name in it, since player names aren't valid variable names ("[RGG] Spooner" is a valid name, but not a valid variable name). You could have an array arranged like this, though:
[ ["[RGG] Spooner", 27], ["*FFF* Trotsky", 45], ["Frodo97", 4555]]
Then you'd need to search through it to find the value associated with each individual player.