I will reach Hangzhou late at 11pm on 22sept & plan to take the 8:00 bus to Tangkou on 24sept.

I am concern that the ticket will be sold out by the time I get to Hangzhou west bus station on 24sept morning
I am a foreigner , is it possible to buy the bus ticket online from Hangzhou to Tangkou in advance?
Or do you know which hotel in Hangzhou can help me to buy the ticket & I can collect when I check in on 23sept night , thanks .