In his Against Heresies Book III, at the end of chapter 3, Irenaeus says, “Then, again, the Church in Ephesus, founded by Paul, and having John remaining among them permanently until the times of Trajan, is a true witness of the tradition of the apostles.” Trajan began to rule in A.D. 98, and John was alive among the people of Ephesus till that time and perhaps a little while after.
In Against Heresies Book V.30.3, Irenaeus writes (declining to try to identify what the number of the beast signifies), “for if it were necessary that his name should be distinctly revealed in this present time, it would have been announced by him who beheld the apocalyptic vision. For that was seen no very long time since, but almost in our day, toward the end of Domitian’s reign.” Domitian died in A.D. 96.
As to John’s actual release from Patmos it would likely have been soon after the death of Domitian, as his edicts – such as banishments – would be voided on his death.
What you are reading is Irenaeus claiming in the first paragraph:
1) John was alive when Trajan ruled in 98 AD
2) John was at that time in the Church of Ephesus, the Church that Paul founded
second paragraph:
1) John kept hidden the number and name of the Beast because it was not time for that to be revealed
2) John is the one with the apocalyptic vision
3) John had his vision towards the end of the reign of Domitian (which confirms Domitian placed John in Patmos)