I purchased the wrong version!
There are three versions of 1Password touch in the iTunes App Store:
1Password Pro. The Pro version of 1Password is a universal binary that will work on iPhone, iPod touch, and iPad.
1Password for iPad. Standard version of 1Password for iPad only.
1Password for iPhone. Standard version of 1Password for iPhone/iPod touch only.
If you already have 1Password Pro, you do not need to purchase 1Password for iPad separately. If you did, please contact iTunes Support and request a refund. We’d love to help you ourselves, but since the App Store is a separate entity, it’s not under our control and so we have to refer you to the iTunes Support team.