There is one shuttle bus everyday operated by Air Asia for their passengers, between Shanghai Huangpu Bus Station (1588, Waimalu, next to Nanpu Bridge Station of Subway Line 4) and Hangzhou Airport. In the event of flight schedule change, this bus service will depart 1 hour after the arrival of AirAsia X flight. You can ask them to book the bus in advance through the airline company. If they miss it, they can take the airport shuttle bus to Hangzhou railway station and then take train to Shanghai.
After arrive in Shanghai, they can catch a taxi to the hotel.