There's a trigger that turns on 'fog of war'... use that. It'll make the whole thing black, but once someone explores an area they will 'remember' what it looks like, and it will be a dull grey foggish thing.
NOTE: Once you do this, the whole map will be covered with a dense fog (a bit like what my map looks like right now, it's very hard to see any distance at all, which is what i wanted for mine, in your map you may want to be able to see farther distances, which means fog of war will not work for u)
To make him see what player 8 sees, make them allies (player - player alliances i think) and then turn on allied vision, or whatever its called.