For #!, it would be unsafe to upgrade to 9.04 at the moment. #! includes a few custom packages which (to my knowledge) haven't been built for 9.04 yet.
If you want to risk it, update your sources.list and replace "intrepid" with "jaunty", apt-get update, then do a "aptitude upgrade". Aptitude has alot more error handling / dependency resolution than just apt-get.
Not really, if the modules are loaded and you don't have the devices then the codepath contained in them will never be executed. All that'll happen is you'll shave a few hundred K off your memory usage. The kernel only really loads modules if they're required, this is what udev manages in the background.
As for the scsi module, that has uses in many areas, esepcially if your using SATA drives. Bluetooth is probably being loaded by the bluetooth applications so nothing to worry about.
A better location would be
That way the code is executed when a network interface comes up.
Also, please note that this script has interfaces hardcoded, making reference to eth0 and eth1, these interfaces maybe different on your machine so please check and edit first before assuming that your covered.