The way that other platforms have done it is by using custom labels - so the messages just get labeled as "snoozed until tomorrow", and at 9am the client simply

The way that other platforms have done it is by using custom labels - so the messages just get labeled as "snoozed until tomorrow", and at 9am the client simply grabs all those and moves them back to inbox and deletes the label. That's how Mailbox did it, for example. Once Snooze is added, I'll happily buy this app for $20+ - I've been waiting for something like this since Inbox and Mailbox were killed off.