2. You do realise that what algorithms you have on your H9 … you will have on your core too? as long as they are registered to the same Eventide ID? Regarding the specific algorithm that comes with the core … you can do a +1 octave with some modulation and play very simple chords if the Type is set to modern … does it sound like a real 12 string? not especially … is it passable in a band or mix? probably.
but then I have never really heard any effect that pulls off a 12 string emulation perfectly, due to the individual tuning first three strings are octave the top three are unison (off the top of my head) … as you can't treat each string individually (without a hex or individual piezo's) you either have to use a detune or octave pitch or a combo of both… then you get into polyphonic pitch shifting … somethings are better than others at this.
regarding the Whammy, again you can set the pitch to the expression pedal and it will sweep the pitches .. but PitchFlex is probably a fair bit smoother and may track better with chords ..well it seems to track differently so I find better is dependant on what you are trying to achieve and what chords etc.