Confucius is an excellent leader in for a Scientific Victory because of his unique Keju ability and how well his strategic Civ choices synergized across the Ages.
The clearest path to a Scientific Victory for Confucius utilizes the Han, Ming, and Qing civilizations, all of which are either his strategic or geographic choices and will help maximize Science output through their many unique features, though there are many other viable options for Confucius and a Science Victory.
As with all Legacy Victory types in a Science Victory requires planning across the Ages toward a final project — in this case, the Space Race.
Confucius can take advantage of the Han's Population-boosting features to maximize Science yields in dense Urban settlements.
The Ming have an obviously beneficial bonus that boosts Science in the Capital by 50% during the Exploration Age, and the Qing's Unique Quarter and Economic proficiency help Confucius secure the Science Victory in 's Modern Age. Overall, winning a Science Victory with Confucius will require leaning into city development and maximizing Specialists in cities as much as possible.