If your using a wf 9wt line you cant modify it into a a taper, i also don't think there is any need for poly leaders on a 9wt outfit anyway. Scientific anglers steel head line is a good line for good turnovers anyway so all i would advise is a tapered mono filament leader and a good fluorocarbon tippet, if its a floating line there is no need for poly leaders, although they do have an advantage on intermediate and sinking lines. Don't do anything to the line and you will get some good distance casts out of it. If your getting better at casting use a DT line as this will increase your distance.