Airport Express Shuttle Bus Service

Hello,
I have voucher for Airport Express Same Day Return Ticket (Hong Kong Station) for making stop over in HK Airport. I have to redeem this voucher after arriving at HK Airport.
- Can I use the Airport Express to travel from HK Airport to Hong Kong Station and then from Kowloon Station to Hong Kong Airport? (the arrival station and the departure station are different)
- Can I use the shuttle bus service from Hong Kong Station to one of the hotels served by the shuttle bus service? and then from another hotel served by the shuttle bus service to Kowloon Station. But I don't have booking confirmation from the hotel. (I just stop over in HK)

Thanks in advance,
Eddy.