I have an 8 hrs lay over at terminal 1 in HKIA. We are planning to go to disneyland, would it be possible?

Yes, it is possible. But as your time is limited, I suggest you take a taxi to get there to seize time, because no direct bus leads to the park! And the taxi fare shall be 100-110HKD.

Anyway, if you wish to take bus, here is the way: take bus no. S1 to Tung Chung. At this metro station, take Tung Chung line to Sunny Bay. Then transfer to Disneyland Resort line to reach!