I have a hunch that there were varied edges to the Old Testament canon at the time of Christ. Most agreed on the Law and the Prophets (although an argument can be made that the Sadducees really only considered the Pentateuch to be canon... Philo also is majorly focused on the Law and considers the Prophets a kind of second level canon).
The Essenes considered various apocalyptic writings Scripture like 1 Enoch. I've wondered if there was some overlap in the early Jerusalem church with the Essene community, and here it seems notable to me that Jude quotes 1 Enoch. At Qumran I suspect they looked at writings like the Hymns and such as Scripture.
The Protestant OT canon today, as well as the Jewish canon today, seems to me to be the canon of the Pharisees, which became the canon of Rabbinic Judaism. Meanwhile, the OT canon of Roman Catholicism and Orthodox Christianity seems to me to be the Diaspora, Hellenistic Jewish canon, which it seems to me was both the OT canon for the NT Greek writers, as well as the canon of the patristic church.
That is my sense of the lay of the land, certainly open for dispute and discussion. It is something like what seems most likely to me given what I've studied of the topic.