My reply is already late though. I also got the message:

I registered on Coinbase because I thought it was a wallet. After I knew the difference between custodial and noncustodial wallets, I moved all my money from Coinbase custodial wallet and I was not using it again till now.
I guess we'll know on April 9, please update us if you can

This is an update. So, it is 9th April and I can still access my account via the app and web without any challenge. There seem to be no restrictions at all when I explored the account. We will see in the next few coming days.
Today is April 10, I was still able to access my Coinbase wallet account. I have no coin on the exchange since 3, 4 or more years ago. I do not want to risk my asset, I would have tried to send some coins there to know what is going on but I won't.