There are no historical first-hand accounts that Revelation was written in the 90s AD. You have only one second hand account by a writer from nearly a century later who makes a vague and uncertain statement:
Irenaeus (A.D. 180), a student of Polycarp (who was a disciple of the apostle John), wrote that the apocalyptic vision “was seen not very long ago, almost in our own generation, at the close of the reign of Domitian” (Against Heresies 30).
From this statement, many others have concluded that Revelation was written during the reign of Domitian citing Irenaeus. Thus, this is NOT eyewitness testimony. It is hearsay and would be inadmissible in any court in America. It could be that Irenaeus misunderstood Polycarp or that his quote meant that what was being revealed to the churches, wasn't seen until John was released in 98 AD.
Domitian quickly regretted his persecution of the churches and quickly stopped the practice while Nero, was called, "the Beast" by many of his days and he relished in killing Christians.
I have studied this issue extensively and there is substantial evidence that John was vanquished to Patmos during the reign of Nero, and not Domitian. The Bible leaves no doubt that the "great tribulation" spoken of by Jesus occurred to Jerusalem in 70 AD. There can't even be a debate about this nor can there be any debate that the presence (or parousia) of Christ returned then as recorded by Josephus. Rev 1:7, 11th :1, Mt 24:34 and so many other places also make this absolutely clear.