I've had/have amps from all 3 manufacturers and owned both the RM-9 and V12i. The V12 will give you that classic Cary house sound with the lush (some might say syrupy) midrange. It certainly is a very flexible amp as well.
The RM-9, while a fine amp (I own a couple of Roger's other amps) is going to be much more neutral and transparent sounding. So I don't think this amp will offer the sound you are seeking.
I have not owned the VAC 80/80, but have owned the Auricle Musicblocs. IMO the VAC house sound, in addition to providing a glorious midrange, offers a very balanced musical presentation. Of the 3 amps listed and given your stated preferences the VAC would be my choice.
The RM-9, while a fine amp (I own a couple of Roger's other amps) is going to be much more neutral and transparent sounding. So I don't think this amp will offer the sound you are seeking.
I have not owned the VAC 80/80, but have owned the Auricle Musicblocs. IMO the VAC house sound, in addition to providing a glorious midrange, offers a very balanced musical presentation. Of the 3 amps listed and given your stated preferences the VAC would be my choice.