As near as I can tell, the author you linked to is not calling the sales tax a VAT, but is calling the corporate tax a VAT.
He calls is a VAT because Cain’s plan does not allow companies to deduct wages from their gross income prior to that income being taxed.
I’m not sure why that makes a corporate tax a VAT, even though I do think wages are a legitimate business expense and should be deductible from income as a cost of doing business.
9-9-9 is a corporate tax, a sales tax, an income tax AND a VAT tax. And this is who the Taxed Enough Already party supports? Laughable.