Dear Colleague,
Many years ago I happened to read a book by Dr.V.Raghavan on the ninth rasa. I do not remember the exact title but could try to find that out from the Visva Bharati library. The difficulty is the the Central Library of the University is rearranging its books when a they have to work with a chronic shortage of staff. Still I shall try with my colleagues.
You can also try with R
ūpa Gosvāmin of the Chaitanya movement. Chinmayee Chatterji had some works on Gosvāmin. But I myself have not read Chatterjee

Best
DB