Actually the mentioned field "Delivery Date" refers the date by which the products in a sales order are expected to be delivered to the customer. It located under the "Delivery section" in the "Other Info" tab of the SO form. Even though ODOO shows the expected delivery date of the product based on the customer lead time of the product, we have to manually enter the delivery date. That's why the user can't see the value for delivery field in the SO list view. If we wanted the know the system calculated delivery date for that SO then he can add the "Expected Date" field into the list view.