Not sure what options you want to sell, but if they are actual SPY options, you want to have actual SPY as that they have physical delivery. In other words, if your call gets exercised, you are supposed to deliver SPY, not VOO or cash. I would not recommend trading VOO options as they are very illiquid compared to SPY, and the costs associated with that are much higher than the measly difference in fees.
There _are_ alternatives if you want to get really fancy.