Is there a Rush Delivery option where I can charge customers extra for delivery on specific days?

Yes, there is! So first, you'll need to create a product and name it "Rush Delivery". Kindly also make sure that this is a Non-Taxable product and set the price of your Rush Delivery Fee. Next, go to eLocal and proceed (Click the Pen Icon) to the Local Zone you wish to add the Rush Delivery option.

 Once done, go to Delivery Control and set Time Slots for your Normal Delivery and Rush Delivery (Click the Rush Delivery Icon) Time Slots. Don't forget to hit Save.

Lastly, kindly hit the Update button.