Oddly enough I managed to get Apple Pay Cash activated on my iPhone X and one of my iPads before they disabled new activations. It's working fine on those two but I have a second iPad where the toggle is not showing up anymore. I think it's a safe bet that they'll get everything working properly within the next 24hrs.
Some interesting things about using Apple Pay Cash with multiple devices that I've noticed:
- Your AP Cash balance is shared across all of your devices.
- Verifying your identity by taking pictures of your photo ID and entering your social security number only needs to be done once on your account, not on each individual device.
- When you add a bank account to withdraw money from AP Cash, that bank account is shared between devices, so you can easily withdraw from any device.
- Funding AP Cash is done through Apple Pay, and uses the cards you have added locally on that device. The card you're using to fund AP Cash is NOT shared between devices - in my case I had to add my debit card to each of my iOS devices so I could send money using them.
- You must activate Apple Pay Cash on each device you intend to use it on separately, and each device is issued a different virtual debit card number (in my case from Discover Debit) when it is activated.
- The AP Cash card does not show up or work at all on Apple Watch at the moment - even if you've enabled it on other devices, and presumably will not until the watchOS 4.2 update is released.
The fact that the AP Cash virtual debit card is issued by Discover probably means you won't be able to pay with AP Cash anywhere Discover isn't accepted.