from shenzhen to airport hongkong

Hi, i need to arrive at hongkong international airport early in the morning at latest 9.00am and i would be departing from shenzhen. i was told that i can't take the ferry for mu luggage will weigh in all around 35 kg..i heard that there is a link between the shenzhen airport and hongkong internatonal airport so that i can take a coach between this 2 destinations..i wanted to know the schedule from shenzhen airport to hongkong international airports and the duration of the journey because am really afraid that i might miss my plane..could u please advise,
Thank you
K.R