Can I give my customer an expected delivery date?

It is not possible to provide the expected delivery date.  However,  you can provide an projected ship date.  The projected ship date will in part be controlled by the "Requested Ship Dates: In stock ship days" and the "Requested Ship Dates: Out of Stock ship days" fields found in Sites > [site name] > Products > [product name] > General tab in the "CheckOut Options for This Product" section.  
 
If the product uses inventory and the inventory is in stock the "Requested Ship Dates: In stock ship days" will be used to determine the estimated ship date.  If the product uses inventory and the inventory is NOT in stock, or the product does not use inventory, then the "Requested Ship Dates: Out of Stock ship days" setting will be used to determine the projected ship date.  
 
The System will look at all the items in the cart and will provide the latest date as the projected ship date. For example if there are two products included in the order which will require different time for shipping, the system will provide the "Projected Ship Date" for the product which will take the longest time to be shipped.
 
You can also allow a customer to request a different ship date.  The ability to select a ship date is determined by a setting in  Sites > [site name] > General Info tab in the "Checkout" section.  The setting is labeled "Capture Requested Ship Date."  If this setting is turned on, then the user will be able to select any ship date that falls after the date set in your in stock or out of stock requested ship dates setting.  When the user selects a ship date, this will be used as the projected ship date.
 
We cannot provide the "Expected Delivery Date" as we cannot anticipate the actual arrival date for a customer combining both the amount of time it takes to produce the job, and the selection they made in the shipping area. Every item in the shopping cart can be shipped to a different location, each can have a different shipping method, and can take a different amount of time to produce. We can only take the longest time to produce out of all the items in the cart and give them an anticipated "SHIP DATE", not an arrival date.

For more details on various ways to configure this setting, please see this page: Requested and Projected Ship Dates