AWS Mobile SDK for .NET and Xamarin Question

I was following the AWS Mobile SDK for .NET and Xamarin guide in the link below to setup our iOS app to Download from an S3 bucket. As a part of the process we have to create a Cognito Identity pool. https://docs.aws.amazon.com/mobile/sdkforxamarin/developerguide/setup.html

A customer has informed us that the Cognito Identity pool is not supported in AWS Web Application firewall (WAF), and they would like to know if it's possible to use a User Pool instead which is supported by WAF. Is that possible or is our only option to use a Cognito Identity pool when using the Sdk?