Before giving your Beosound 9000 to repair or for laser replacement try at least to clean the laser lens. Now, when the service manual is available it's not a big deal. Simply follow the instructions 1 to 9 on pages 6.4 to 6.7. Be only careful with a clamper arm assembly as the external part goes through the internal one. When you reach the laser lens ( you dont't have to dissassemble the CD mechanism, just the cover) clean it with a microfible for glasses. If you want to use liquid - use distilled water from pharmacy ( for injections) . Don't use any alcohol nor isopropanol as it may damage lens surface.
My last researches about cleaning liquid shown that 30% alcohol with 1 small drop of washing liquid can be used as well.