11 9s of durability is about the likelyhood of AWS loosing your data. It doesn't cover the likelyhood of you being able to access your data that's called availability.

For example on GCS (Google's S3)...A storage class specifies how many locations the data is made available. All storage classes share the same durability (chance of google loosing your data) of 99.999999999%, but have different availability (chance of being able to retrieve data).