There are many trains from Hangzhou to Shanghai daily, with the earliest one departing at 01:49 and last one leaving at 21:36. Since you’ll reach Hangzhou at 10.30pm, you could not catch the last train to Shanghai. So, you would better take a taxi to the railway station area and stay one night there. Next day, you could take the G-train departing around 7am, such as G7362, G7302, which will reach Shanghai before 8:00am.