Yes. Once you have subscribed to the app, the "Enable This Device" link on the Subscribe screen (which you can find by tapping either the "Search" or "Picks" icon) helps you gain access to WineRatings+ on your other devices that use either the same iTunes/App Store account or the same Google Play Store account. Tap this button and enter the same store email/user name and password you used to subscribe to the app in the first place. You'll instantly gain access to wine ratings without needing to re-subscribe.
The devices must be tied to the same account. A single subscription cannot currently be shared across Android and iOS devices, as they are sold through different stores to different accounts.