@Keith - I realize the OP was talking about 9.8. But the symptoms, for lack of a better term, seem exactly the same.
I've already seen that link, and they're talking about a guest SSID with the captive portal. Maybe it's the same issue, but it seems the train of thought there is the reauthentication on the portal is causing the problem. We're not using a captive portal for these iPads.