If I delete a message with a single tick, does that just get deleted from my local device ( Android) or does it no longer get delivered to the recipient?
If you wish to stop a whatapp message from being delivered to a recipient, I have found that after you have sent this (✅) and before this is delivered (✅✅) you add the person temporarily to your block list until they come on line next as you can still see there date stamp. The message then doesn't get delivered. You can then reinstate them and the message will never get delivered and stays in the status of ✅. Hope that helps.
Whatsapp marks messages that have been delivered from the sender to the Whatsapp servers with a single tick, and messages delivered from the Whatsapp servers to the recipient with two ticks. After the single tick has appeared, the message is already on the server and can't be removed/aborted.
If your data connection is slow/unavailable, you can cancel the message by deleting it before the tick appears.
I tried deleting a single ticked message which I sent to another WhatsApp account of mine, but it got delivered even after that as soon as I logged into the other account. So it looks like deleting a message with a single tick only erases your local copy.
If you had internet / mobile data when the message was sent, then there is high possibility that the other person has already received it. So, deleting it from your phone doesn't matter.
More or less, it works the same way as SMS.
Single tick denotes message delivered at WhatsApp server. Double tick denotes message delivered to destination, i.e., to whom it was addressed.
At single tick status, the message was delivered but not yet delivered to receiver, block the receiver.
Keep him blocked till he opens WhatsApp. Of course you don't know when he will open WhatsApp. So don't unblock immediately.
If he opens WhatsApp while blocked by you then your message will never will be sent to him even if you unblock him.
Try it and confirm.