No, your client has to create a Glide account, an organization, initiate an app with a first draft of gsheet, and add your own email address as a member of the org. So you will be able to work on his app. And when you will implement the buy button, your client will have to enter his Stripe credentials to connect his glide account with stripe.
Not the best way to proceed as an app builder, but the only way to do as of today.