Let me confuse you a bit more then!

Crutchfield lists:
Here Welcome to 21st century radio! Connect the KTC-SR903 SIRIUS tuner to your compatible Kenwood receiver for more than 120 channels of cutting-edge programming, including news, sports, entertainment, and 65 channels of commercial-free music!
The KTC-SR903 tuner is compatible with all 2002-04 Kenwood changer-controlling receivers (also with select 2001 models), and this compact unit fits almost anywhere in your vehicle. You can select channels by category or by number. Station information (artist, album title, track title, channel number, or channel name) displays on your receiver's readout (information on display may vary, depending on the receiver). Read more
Key Features:
tuner module connects to all 2002-04 Kenwood changer-controlling receivers (and to select 2001 models)
single-cable antenna connection (dual-cable SIRIUS antennas are not compatible)
SIRIUS-compatible antenna (not included) and subscription required to receive satellite signal
SIRIUS offers digital-quality sound, coast-to-coast coverage, and more than 120 channels of music, news, sports and entertainment for $12.95 a month (plus a one-time $15.00 activation fee)
select channel name, channel number, artist, song title, or category name to appear on receiver's display
channel scan/search
channel presets
CD changer port lets you add the SIRIUS tuner and retain changer controls
RCA outputs
7-9/16"W x 1-3/16"H x 6-1/8"D
warranty: 1 year
Important Note: The KTC-SR903 uses a single-cable antenna connection, so be sure to purchase a compatible antenna (see Recommended Accessories).
Its only $50. I think CD changer cables have been standardized for a while, so I would think you would be ok with this. I think your headunit is only a year old right, considering the 979 is this years model, 969 is probably last years model.
Any antenna will work (Sirius wise) Terk or Kenwood. I have a Terk attached to my Clarion and have no problems. I also have my antenna on my rear deck instaed of outside the car. You can kind of see it though the rear window, but it isn't sticking out like a sore thumb on teh roof or decklid!