Me n bf will be in HK nxtwk,will arrive at 7am, what's the best place go from rambler oasis hotel

The three scenic spots you mentioned are must-sees in HK. Your hotel offers free shuttle buses to Tsing Yi MTR Station.

To Disneyland, take Tung Chung line at Tsing Yi to Sunny Bay, where transfer to Disneyland Line to the park.
To Ocean Park, take Tung Chung line to HK Station and walk to Central. Near Central Pier No.7, take bus no. 629 to the park directly.
To Giant Buddha, you can still take Tung Chung line and get off at Tung Chung Station. Walk to the cable car station to take the cable car onto Ngong Ping and walk to the Buddha.

Except them, the Sky 100 near Kowloon, Kowloon Park, the Peak, Tsim Sha Tsui/Avenue of Stars and Causeway Bay are also good destinations. For shopping, you can go to Tsim Sha Tsui and Mong Kok.