Which bus do I need to take from Xiaoshan airport to XiangTing Inn Hotel in Maojiabu Road Xihu?

You can take shuttle bus Pinghai Rd Line to Grand Metropark Hotel and then take bus 27 to Maojiapu. Then, walk east for 5 minutes to the hotel.
To east station, take bus 27 to Yuewang Rd and then transfer to bus 105 to the east railway station.

How long does it take?

It takes about 1h to the hotel and 40mins to the east station.