The answer is to find the right balance.
Consider an unstructured life where every morning you wake up whenever you feel like, and then it's just a blur of activities and a rushed morning routine. The whole day and night can be like this - you're spontaneous and do only the things you want to whenever you want to. Inevitably, such a lifestyle will lead to stress and lack of productivity.
The other extreme is to enforce a rigid structure and you beat yourself up every time you deviate from that strict routine. This also leads to stress and yes, this may kill your creativity.
Find the right balance. If you feel that your daily routine is too strict, relax a bit. If you go off the rails for a day, no problem, just get back on track the next day without obsessing about it too much.
A routine can help your creativity as long as you don't allow it to become a rut.