Airport transfer and baggabe check-in

Well, it is L'hotel Nina ET Convention Centre, right? The best way should be to take the airport shuttle bus no. A31 and get off at Tsuen Wan West Raiwlay Station Bus Stop. After that, you can easily walk to your hotel in sevral minutes.
As for the checking in on the back way, I do think it also can be a good way by bus no. A31. The whole journey takes about 60min, so you'd better take the bus earlier to check in at the airport. By the way, the bus wil take you to the T1.