Alex,
There are two ways to go about this.
1. If you truly mean Home Theater, you will require a surround sound processor of some sort. Bang & Olufsen makes a terrific one, but you can use another brand. Simply make sure that it has dedicated Pre-Amp Outputs. The BeoSound 9000 will connect to the Surround Sound Processor using an Aux Adaptor as any other CD player would. You will need PowerLink dummy plugs for the PowerLink sockets to the output to work properly. The BeoLab 1s will connect via single RCA cables to the Pre-Amp Outputs for the front right and left channels. Other speakers would fill in for the center, rears, and sub, or you could simply leave it on two channel.
2. Otherwise, if your question simply implies that you wish to leave the BeoLab 1s and the BeoSound 9000 as a set and play televisions sound through it, this could be tricky and not nearly as elegant to operate as the first option. Since you have at least the two sources you've mentioned (television & DVD) and the BeoSound 9000 has only one Aux input, you'll need to use a switcher of some type. You'll also need to ensure that your television has a line out like the DVD player.
You must remember that the BeoSound 9000 is an audio device and was designed to handle audio tasks, which would not include video. That being said, anything is possible, but I always try and adjust my clients' expectations when going outside the recommended use.
Good luck!
There is scarcely anything in this world that some man cannot make a little worse and sell a little more cheaply. The person who buys on price alone is this man's lawful prey. - John Ruskin