At what age (if at all) is it considered safe for a child to wear a hood while sleeping?

Red Nose does not have any specific information about the use of hoodies & sleep for the older child (over 12 months)
However, there has been some concern expressed about toddlers & older children wearing hoodies for sleep & the risk of choking (if hoodie has a cord) or getting stuck with face covered when moving during sleep.

I notice that Product Safety Australia does not include hoodies as a part of their mandatory safety guidelines for Infant/Child sleepwear.
https://www.productsafety.gov.au/standards/nightwear-for-children 

There may be other specific circumstances where the wearing a hoodie (or other head covering) should be avoided eg Child Care Services