How to Show Apple Wallet without Apple Pay — Boarding Passes Only (iOS 10)
For devices supporting Apple Pay, the feature cannot be disabled and is shown at the top of the Wallet app. There is no option to hide the feature or disable it using Restrictions.

Double-clicking the home button only works if there is a card in Apple Pay, upon which the default Apple Pay card is shown and other Wallet cards/passes can be presented. Unfortunately without any Apple Pay card this feature is unavailable.