Hi, I'm planning to go from HK to Shenzhen Airport to catch a 9 A.M. flight. I heard that there is a bus from HK to Shenzhen Airport in the morning (around 6.30 A.M.?). Do you think it is possible, to go from HK to Shenzhen Airport aroudn 6.30 A.M. to catch the 9 A.M. flight out of Shenzhen? Considering the immigration process and everything

Thank you