Positions 1-9 matter so little you almost don't have to even worry about it.
I saw this in surival trial, where you're initiative is an average of all your ninja put together.
Sometimes I could go first if was in 1 as oposed to 4 which I usually put.
Also attribute matters.

http://forum.naruto.oasgames.com/en/forum.php?mod=viewthread&tid=1258&extra=page%3D1