I just got the 9855, love it. One problem though, my cd is stuck in there, open won't work, and also the tilt function doesn't work either. Among a few other problems, I need to send it back to the manufacturer.
I would try to slide the unit out of the metal sleeve it's in by removing the trim ring and pushing the tabs in on the sides of the unit itself with a flat-head screw driver or equivalent. All headunits have different places with which to do this, so you might have to work at it a bit to remove it.
I have the alpine 9853 and I same problem with the cd being stuck and the tilt not working. I just kept pressing the reset button (about 6 times) until it opened and ejected the cd.