Does lift generation create a vacuum over an airfoil?
I think this is simply a terminology issue. 

There is no vacuum in the physical sense on the upper surface of an airfoil. There is an area of low pressure, though, which in certain context is also called a vacuum. 

A great example for this linguistic imprecision is my vacuum cleaner, inside of which there is no vacuum in its physical sense by far, but clearly it sports considerably lower pressure than the atmosphere in the rest of my living room.