My knowledge on this theory itself is pretty lacking; my only experience with it was from a single biblical studies class. The basis of it was more or less that the book of Revelation is just one big metaphor for the Judean revolt in 66 AD and more specifically Rome's stopping of it.
I was wondering if this theory was a purely modern one or if this was actually something that Roman scholars of the bible might have believed. As a secondary question, if they did subscribe to this theory, how did they negotiate it with their Roman citizenship?
No.
There isn't a huge amount of commentary written on Revelation in the early church, but what there is does not adopt this approach at all. In Latin, the influence of Victorinus, Tyconius, and Jerome, oriented the interpretive tradition to take it spiritually, eschatologically, and broadly millenialist. Almost nothing in the Western tradition takes it as referring to the Judean revolt.
Among Greek authors, you have to wait until the 6th century before a surviving complete commentary appears, from Oecumenius. Between he and Andrew of Caesarea, you again get a view that does not take it in the Judean revolt sense. Instead it is mainly spiritualised, and concerned with Christ's second coming.