Continued the same playthrough as mentioned before and still landed k9. Olivia herself suggested to promote MC to k8 when Chanel recommend to leave him on k7.Just make sure you max your SisTeam points (Olivia)....providing you actually do align with her and will support her. If you don't then I don't think it is possible. Need to appease her to get her to give you max rank at the time.
Don't need her route for it no but it's the simplest/quickest way to get K7 'early'. However, once Dominique promotes you (when she shows you your 'upgraded accomodation'), the next morning Junko will visit you, you can just dump Junko at that point by refusing her 'services' with no repurcussions.
Junko romance only really important for the revolution path/ending as you have to be on her route in order to get on it.
Anyhow now done with season 1 but I am considering waiting for few more updates before starting S2 so there is enough content.
Thanks for all your advice. You have been very helpful.