I think because children are still learning and exploring at an early age, that opportunity to be allowed to explore, discover, and create is closely can also impact their creative ability. So, I think the latter should be taken into consideration when looking at the relationship between cognition and creativity for children.
This is an interesting field and there is a much wider implication which maps over to the Educational domain and the Child Development domain. For example, Piaget's theory of cognitive development would suggest that the cognitive development of a child is situated in schemas and the question need to be situated in a child-friendly way otherwise the child may not understanding.
Others child development theories such as Bandura social learning theory suggested that the development of the child is dependent on the social context and that the social context supports the development of the cognitive schemas. Whereas Vygotsky would extend this and suggest that learning linked to a 'little bit of help' (zone of proximal development). Arguably, the child who as experienced these factors is more likely to work creatively as there is a context and schema to problem solve from.
Problem-solving and creatively is integrated within the primary school curriculum across all the core subjects. Based on my experiences and discussions the child is taught cognitive strategies (sequential steps) and then asked to use a range of cognitive strategies overcome the problem, which often requires creative thinking.
Again, arguably problem solving and creativity can be based on cognitive strategies or innovative insight or both.
I think because children are still learning and exploring at an early age, that opportunity to be allowed to explore, discover, and create is closely can also impact their creative ability. So, I think the latter should be taken into consideration when looking at the relationship between cognition and creativity for children.