Basis the incoming phone number received from WhatsApp our Opt-in manager add it to records. If the phone number that we received from WhatsApp doesn't have digit 9 the same will be recorded on our system. When you try to send a message by manually altering the recipient phone number you will not be able to do so because such a number doesn't exist in our system and also the opt-in manager doesn't recognize such a number. WhatsApp forwards us a number which is valid and approachable. Hence, you are not required to add digit 9 as WhatsApp will take care of it.