I don't know if it's the same setup as my 1995 900 or not, but see if this
describes what yours is like. The radio has 4 holes and the SID has 2. If
so, this is how I removed mine.

Take a wire coathanger, cut both ends off, so that you end up with a pair of
LONG "U" shaped pieces. Reform to a true "U" shape to conform to the pairs
of holes in the radio, deburr the ends. You can buy this tool at Crutchfield
if you want.
http://www.crutchfield.com/S-gMkCGM9dy2h/cgi-bin/ProdGroup.asp?g=754&avf=N&searc
h=installation%20tools

Here's how it should look:
http://www.crutchfield.com/S-gMkCGM9dy2h/cgi-bin/ProdView.asp?g=754&id=morephoto
s&pi=2&i=120865618&display=L#Tab

The tool needs to depress a couple of clips to release the unit. You may
need to push outward on the tools as you pull on the radio. On mine, I can
stick a couple of fingers in to the cassete slot to get a grip on the radio.
If you need to disconnect the plugs on the back of the radio, make sure you
have your radio code available. Also, you will lose all your presets. Be
VERY careful with the antenna wire plug: it breaks quite easily.

To remove the SID, I bent to tools back to approx. 90° and just used one end
in the single holes. If I recall correctly, it was somewhat tricky to
release the clips on the SID. You may be able to get one hand thru the radio
opening and reach up and push the SID outward as you release the clips.

Good Luck,

Jim M