Installing OS 9 system support from Tiger

I need to install the OS 9 system support in order to run Duke Nukem on my iBook G4. If I install it from the OS X install disk, will I lose anything on my hard drive? I don't think it will, I just want to be sure.

Also, I have another question. In order to get into the classic mode you would just go to System Prefs - Startup Disk - and the classic should be there, is that correct?

I believe that the OS 9 is in the optional software. I forget which disk it is on. You should be able to install it without effecting your environment. As for running it, all you need to do is run the OS 9 application and it will start up the classic environment.