@AmeliesUncle: I'm always going to go with the answer from the organization itself and not the internet, but there are a few reasons why I was wondering about this. I only have an LLC EIN, and the instructions all sound like you can't go back and get a sole proprietor EIN if you already have one. I want to do business through my LLC and have that information be consistent on everything, and that's what the IRS confirmed. You have to put your LLC info and EIN on your taxes, so it doesn't make sense to use a different sole proprietor EIN on your W9. I'm not giving out my SSN.
I've seen people say that they use an old sole proprietor EIN from before they started their LLC, but using different EINs on your taxes and W9 forms seems like it could cause issues. No one that raises that issue online seems to get an answer about it. The IRS said that filing your LLC EIN on your Schedule C confirms that it's you. I expected to be on the phone all day, but they call you back if you leave a number. I plan to call again with some other questions, and confirm this one. My accountant also confirmed this. Calling for clarification is always the best option.
