A study by Amber Y. Wang gives us reason to think so: students who spent more time reading and writing performed better on creativity tests.
The study only investigated the correlations however, so it can’t tell us what’s cause and what’s effect. Reading and writing might indeed lead to more creativity, but it’s also possible that creative people naturally feel more drawn to reading and writing, or that other factors influence all of it together: reading, writing and creativity.
What we can say in any case is that both reading and writing are related to creativity.