Can't download 'already purchased' app after device crash
The most probable source of your problem is Apple just changed their terms and conditions for the App Store and they won't let you download anything till you accept them.

Whenever Apple change their terms and conditions, the App Store app has a strange behavior (since I had an iPod touch in 2008). One typical situation is that it won't let you download an item that you had already bought.

What you should do is install a new app (one you have never downloaded). Then it will take a lot of time and finally (and hopefully, otherwise you should kill the App Store app and begin the process again), the new terms and conditions page will appear for you to accept them.

Once you accept the terms and conditions, you'll be able to download your previously downloaded app.

As you see, the problem doesn't have anything to do with the iPad crash but with the coincidence in time with the terms and conditions change.