OSSystemExtensionErrorDomain error 9 while trying to run the SimpleAudioDriverExtension

Video: https://developer.apple.com/videos/play/wwdc2021/10190/

I'm trying to run the sample code from the SimpleAudioExtension workshop I get a validation error for OSSystemExtensionErrorDomain. Is there something that is missing from the instructions that is required to work around this error? If not, how would one work around this?