I'd drive, I never trust Disney transportation when time is important. And the skyliner has had its issues.
However, just be aware that if you do take the skyliner, there is a transfer you have to make at Caribbean beach so there could be a 2nd line, but I doubt it would be much of one, but there is the potential to have to wait on 2 lines, though I do not know that many people will be leaving HS at that time - perhaps all those that did not get into a boarding group.