I would use an MCL2A kit. This is the original linksystem for your BeoCenter 9000. To use a BeoLink Passive on your BeoCenter 9000 you first need a BeoLink Converter to be able to connect ML to your BeoCenter and I am not sure if this will work 100%. An MCL2A can be connected directly to your BeoCenter and is the easiest and cheapest solution.