Amazon RDS MSSQL permissions on the Master database

IHAC running MSSQL 2016 SE in an AWS RDS instance, the customer application requires this permissions on the Master database: Create DB, create DB backup, “grant view”, any definition.

sql_engine_version_2016 = "13.00.6435.1.v1" sql_family_2016 = "sqlserver-se-13.0"

Is that possible to grant this access? He is getting a "permission denied" error using the master user credential. Thank you