Shakespeare’s works were the fruits of a mind unfettered by convention. Creativity isn’t fostered by pedantry, though perhaps an appreciation of other people’s creativity might be.
I sometimes think that the emphasis on creativity in school writing classes is just an excuse for teachers either too lazy or too ignorant to teach grammar and spelling. The truly creative will learn to write even better and the rest of the little squids will at least write their boring prose in a readable format.