about facebook 9 photo friend box on the left of timeline?

Not necessarily (and you can change the number of people in the box so, by that logic, if the same people show up, but your friend is only showing 6 people, what happens to the other 3?). So recognize that, like with a lot of FB, it is not a mutual back and forth relationship where everything you do, they see, and vice versa.

Want to change the people in your box? Usually there's something you can click on (and it's escaping me at the moment) where you can either get it to always show someone or other, or to change the number of people you see.

it was possible to choose who you wanted from your friends to show up a while ago, aand choosing the amount of friends in the box is no longer an option either. you can confirm this by clicking the pencil at the top of the box on the right. there's no way to choose who you want to be in that box.