Configuration and cost management for iam user

Yes, via tagging the fleet and stacks properly. You could only allow the IAM User the ability to create fleets and stacks where the tags match what you have set for the user. Then designate these tag(s) as cost allocation tags.

See:

• Controlling access to AWS resources using tags
• IAM tutorial: Define permissions to access AWS resources based on tags
• Applying Attribute Based Access Control in AWS - Workshop
• Tagging Your Amazon AppStream 2.0 Resources