Okay, If I were there, I would like to arrange the 8 days like this:
Day 1: disneyland
Day 2: ngong ping 360 cable car and the Big Buddha in Lantau Island, back to Tung CHung and shopping and Citygate Outlets
Day 3: ocean park， victoria peak
Day 4: museums (Space Museum, Science Museum all in Tsim Sha Tsui area, can be reached by walking from Avenue of Stars), avenue of stars, then walk to Hung Hom Ferry to take Voctoria Harbor ferry, see symphony of lights around 8pm
Day 5: Wetland Park
Day 6: Repulase Bay, Stanley Market
Day 7: why not having one day to Macau?
Day 8: free, do some shopping perhaps