That page appears to be full of inaccuracy -- my best guess, it was updated months ago before the final specifications were publicized, and not revised before it was posted. At some stage of development, they were probably going to put the normal A8 in both models, then decided later to go for the A8X in the 9.7" device, and maintain the A7 in the Mini line.
Example innaccuracy, the GPU in the iPad Air 2 should be a PowerVR GX6650, a 6-core part, not the same 4-core PowerVR GX6450 from the iPhone 6/6 Plus -- at least, to get the performance Apple claims on graphics.
On top of that, Apple has to have seen the flack they've caught over selling the iPad Mini 3 with no new SoC -- so if the store/iPad marketing pages were wrong by showing the A7, surely they would have corrected it by this point. It only harms sales otherwise.
tl;dr -- Definitely a typo at this point, given all of the other pages that claim to the contrary.