Having done this one my first and second 9000, as well as a Peugeot, the task was similar and it isn't so difficult as you'd think.
From memory:
Removing the top of the dashboard.
1. At each end, remove the speaker grills, to access bolt heads. Do not lose/drop/forget spacing washers.
2. Remove screw top middle of the binnacle.
Removing Binnacle
1. Release retaining clips around the edge for wiring, and any other retaining screws.
2. Should be a straight, but careful, lift out from here.
There are four bulbs that illuminate the dash. They are in thumb/finger-turn holders, so I would make sure that contacts are clean and in good order, before replacing bulbs. When I did this on 9000 Number 1, the top two on either side were blackened - changing them made all the difference.
HTH