You don't need to reinstall 9.1 before installing OS X. They are two distinct systems.
Safari is included in the OS X install disks, so you shouldn't have to download it. Once OS X is installed, use Software Update in the System Preferences to update Safari, if it needs it.
IE for Mac is the worst of the worst browsers you could use. It hasn't been updated for OS X for five years or so — Microsoft abandoned it for Mac — and IE was a bad choice even for OS 9.
With OS 9, I use WaMCom's Mozilla 1.3.1 with the most recent Flash and other plug-ins that are available, along with other tweaks to the browser, and have only a few problems with the occasional sites that use newer versions of JavaScript and Flash that OS 9 can't use.
But if you can avoid OS 9 and use OS 10.2 at the very least — but preferably a newer version of OS X — do so.