Even 9mm is a lot, the DG-300 had a similar problem and it was found that the root rib was deforming under closing loads. Check the mounting of all spoiler controls.........looking for a loose rib or mounting pads, etc. Check the whole spoiler by trying to move it up-dowd, for-aft, Inboard-outboard to see if the pivot points are loose. Some sing very wong here!
JJ