First off sorry because I don't do things through the GUI.
Why do you want the touchpad disabled ? if it's because your palm hits it when typing then just enable the option "disable touchpad while typing". If you want to disable it completely just open a terminal and type
to re-enable it just do
test it out and see how you get on, any changes will not be permanent and will reset when you reboot. To make it permanent just edit your /etc/rc.local file
add this line just above exit 0
and save it.. make sure you test it properly first before you make it permanent.
How you finding 9.10, personally I think it rocks ! loadsa little things that niggled me are now sorted and my 7 second boot time went down to 6 seconds