For some reason, Premiere 9 doesn't recognize my You Tube username and password. I double-checked to make sure I had the right information, but Premiere 9 says that is wrong. This is the first time I've ever had this problem during uploading. Does anyone have any suggestions?
Welcome to the forum.
Unfortunately, you have posted to the Tips & Tricks forum, where no one is likely to see it. I will try to get it moved to the main PrE Forum.
Now, can you sign into your YouTube account from the YouTube page?
If so, then you can Export/Share from PrE, for YouTube, and just upload from the main YouTube page, while you troubleshoot the issue with PrE and YouTube - so all is not lost.
For specs. on which settings work best for YouTube, should you need those, see this FAQ Entry.