I think a 9 or 10 should do it. My vertex waggler is an 11 and I find it's a bit of a faff with nearby bushes/trees etc when I'm not casting far. Regretted not going smaller for the sort of fishing I'm doing. That said I realise a lot of people prefer the length for playing etc.Before you buy also think about the type of venues you will fish.
10 to 12 feet doesn't seem much in it but in a tight swim and fishing to the side a longer rod can add problems.