Maintenance for the week of October 5:
• [IN PROGRESS] ESO Store and Account System for maintenance – October 8, 8:00AM EDT (12:00 UTC) – 12:00PM EDT (16:00 UTC)
I don't see how until you have the access code from the physical edition you ordered. It is sealed inside. If Amazon had access to it then others could also steal the code without opening the box.
Pre-purchase means that you're clearing payment ahead of time for a product to be released in the future.
Pre-order means you intend to purchase upon release but have not been charged yet.
The digital pre-purchase is the only method being honored, as ZOS can track refunds and cancellations and thus remove the Senche from those accounts. The Senche is basically a thank you for spending the money now.