I can't speak for the 9250, but I have a Firestream 9170 running in Ubuntu 8.04. If you want both cards to run, I can't help you with that, as I haven't had much luck with getting 2 Firestreams to be recognized by CAL in Linux (in Windows, I have gotten this to work). As for connecting a monitor, why would you have to do that? Here's my xorg.conf file:
# xorg.conf (X.Org X Window System server configuration file)
#
# This file was generated by dexconf, the Debian X Configuration tool, using
# values from the debconf database.
#
# Edit this file with caution, and see the xorg.conf manual page.
# (Type "man xorg.conf" at the shell prompt.)
#
# This file is automatically updated on xserver-xorg package upgrades *only*
# if it has not been modified since the last upgrade of the xserver-xorg
# package.
#
# If you have edited this file but would like it to be automatically updated
# again, run the following command:
# sudo dpkg-reconfigure -phigh xserver-xorg
Section "ServerLayout"
Identifier "Default Layout"
Screen 0 "aticonfig-Screen[0]-0" 0 0
EndSection
Section "Files"
EndSection
Section "Module"
EndSection
Section "InputDevice"
Identifier "Generic Keyboard"
Driver "kbd"
Option "XkbRules" "xorg"
Option "XkbModel" "pc105"
Option "XkbLayout" "us"
Option "XkbVariant" "intl"
Option "XkbOptions" "lv3:ralt_switch"
EndSection
Section "InputDevice"
Identifier "Configured Mouse"
Driver "mouse"
Option "CorePointer"
EndSection
Section "Monitor"
Identifier "aticonfig-Monitor[0]-0"
Option "VendorName" "ATI Proprietary Driver"
Option "ModelName" "Generic Autodetecting Monitor"
Option "DPMS" "true"
EndSection
Section "Device"
Identifier "aticonfig-Device[0]-0"
Driver "fglrx"
BusID "PCI:9:0:0"
EndSection
Section "Screen"
Identifier "aticonfig-Screen[0]-0"
Device "aticonfig-Device[0]-0"
Monitor "aticonfig-Monitor[0]-0"
DefaultDepth 24
SubSection "Display"
Viewport 0 0
Depth 24
EndSubSection
EndSection
You shouldn't need to edit this though. Just run sudo aticonfig --initial -f.