9 hour layover for flights in and out T3 - Nearby hotel (Cordis) booked - Entry permit needed

Hello, we are a little family with two toddlers transiting through Beijing international airport from New Zealand to Germany. There are 9 hours layover, so we booked a room at the Cordis Hotel. We arrive at 4 in the morning and flying out at 12 lunchtime. 1) is this enough time to get and rest at the hotel? 2) Do we need to apply for the entry permit? Thanks for you advice