The Hebrew text of the Bible passage (Gen 49:10) you try to understand implies that:
1) the tribe of Judah, starting from a crucial moment, would receive (from God) the honor to have kings on the throne of Jerusalem (until the latter existed!);
2) in another (subsequent) crucial moment, a special individual would receive this honor (that the tribe of Judah received for a previous period).
This understanding does not rule out the possibility that before the entrusting of the assignment to Judah as kingly tribe, another tribe could receive this honor. In fact, God chose the Benjaminite Saul as first king of Israel.
In the same chapter, to the verse 27, God (through Jacob) prophecied about the remarkable actions – related to the people of Israel – characterizing the tribe of Benjamin. Referring to the start (‘morning’) and the end (‘evening’) of the state-history of Israel, we read there: “Benjamin— as a wolf will he tear to pieces; In the morning he will devour the prey, And in the evening he will divide the booty.” (Darby)
It is very interesting the comment of John Gill (bold is mine): “Some apply this to particular persons of this tribe, as to Saul the first king of Israel, who was of Benjamin; and who as soon as he took the kingdom of Israel, in the morning, in the beginning of that state, fought against all his enemies on every side, against Moab, Ammon, Edom, the kings of Zobah, and the Philistines, and the Amalekites, 1Sa 14:47 and to Mordecai and Esther, who were of the same tribe, who after the captivity, and in the evening of that state, divided the spoil of Haman, Est 8:1 this is observed by Jarchi, Aben Ezra, and Ben Gersom.” (John Gill, Exposition of the Bible; on Gen 49:27).
Far from trigger a contradiction, these passages harmonize themselves and confirm us for the nth time that the Bible is fully trustworthy.