Does AWS actively and by design parse and keep track of personally identifiable information of the data that AWS customers store on their S3 buckets? If that were the case they would absolutely be subject to CCPA (and GDPR) requests for deletion.

However, I suspect that is not the case. AWS is agnostic as to the type of data stored on S3, and deletion of PII stored on S3 is the sole responsibility of the AWS customer that chooses to store it.