The last information we were given from the school (late July) was that Tin Wan wouldn't be ready for this academic year. There was a chance that it would be able to open after Christmas but if not, it would open next September.
From what I can gather the problems are to do with traffic/parking, objections from local councillors that the school provides no benefit to local residents (as opposed to the derelict shopping centre it replaced), and that it will mean the remaining local shops will lose business.
I think the school are trying to argue that lots of kids will get buses (although I am sure there will still be a significant proportion of Vellfires double and triple parked on the road directly outside the school gates as their little darlings couldn't possibly walk!). They are also apparently offering free evening classes to local residents and free or discounted use of the sports facilities.
There was a SCMP article on it a few months back, I'll see if I can dig it out...