Is there a way that Oracle Service Cloud can show if a customer reads or opens an email that is sent from an agent via outgoing email?
Incident delivery receipt
With standard product functionality there is not a way to determine if an outgoing email was opened or read by the customer. As far as "Incident delivery / read receipts" are concerned, industry best practice recommends managing exceptions rather than utilizing read receipts. It is best to manage bounced emails and invalid emails rather than all successfully sent incidents.
For information on how to manage bounced emails, refer to Bounced E-mail message handling.