Nina,
The 'option' key during startup is not supported on the Wallstreet, only the Pismo and newer. The Wallstreet can be quite cranky when running OSX, so here are a few suggestions and comments...
-Sometimes, at least on my Wallstreet, once you are booted to an OSX Install CD, it will always restart to the CD. I work around this problem in this manner: When you click Restart from the menu or force a restart using 'control-command-power' (this is the least desirable restart), have your opened paperclip ready. Once the display goes black and the CD-ROM drive has spun down, immediately eject the CD tray with the paperclip...it should now start to the HD.
-Even if you had a successful First Aid run, the Wallstreet may not start for any number of reasons. First Aid makes directory repairs but cannot fix corrupt or missing software.
-It may be desirable to erase the HD and install a fresh copy of OSX from your CDs. Don't worry...OSX is machine-neutral...the same software is installed on all models.
There are a few requirements for installing OSX on the Wallstreet:
-a minimum of 128MB of RAM
-if the HD is larger than 8GB, it must be partitioned in this manner:
http://docs.info.apple.com/article.html?artnum=106235
See if your 9.x CD will boot; you can then get details on RAM, CPU speed, and HD from the System Profiler. (I forget...you may be able to access the System Profiler when booted to the OSX CD.)
Not knowing your expertise in these matters, if you have any questions about installation on the Wallstreet, please ask.