Puzzles and Problem Solving
I do not believe that any formal course of study can teach "Creativity" as effectively as can the study of puzzles and logic puzzles. Puzzles (especially of the take-apart types, and the put-together types, and the 3D interlocking types, and the topological entanglement types) are self-contained wonders, which enforce their own clever mechanical logic. Without a "solution sheet", a student is left with only observation skills, experience at moving blocks within mechanical constaints, and pure mathematical logic. When puzzles are presented in a way which encourages development of these skills, but without introducing excessive frustration, the results can be confident creative thinking and an ability to face problems with enthusiasm and determination.
There are also many books of purely logical puzzles. These can help develop independent reasoning ability and many of the abilities are also encouraged by the mechanical puzzles. One's best Mathematics teacher ought to be one's self. However, good books and good puzzles can help a lot!