WotAs - without a shadow of doubt, take the MagLev. It's a quick taxi from where you are to LongYang Station, and a cheap and cheerful (not to mention AMAZINGLY quick) ride to the airport. You don't want to get stuck in traffic in Shanghai, least of all when you're pressed for time.

CX lounge in PVG is nice, but not the most amazing you'll have seen... I'd say aim to get to PVG for 9.30-9.40, so you should leave the hotel in a taxi by 8.45ish at the latest.