W-9 for rent payments?

[Sarah Young]

I recently put new tenants into one of our rentals.  The employer is paying the rent and it is being direct-deposited into my bank account. The tenant sent me a W-9 form to be filled out and returned to his employer.  Is this common? I'm leery of being seen as a W-9 employee by their company. Do I have to fill this out and return it? What happens if I don't? WWYD? 

Thanks!