I have made audio players in Delphi and Xcode but would like to make a player and recorder in XOJO. Can it be done purely in XOJO as it stands or do I need to buy some plugins, possibly from MonkeyBread?
You can play Audio in OSX and Windows with MoviePlayer.
You can record with commandline tools (sox or other)
see https://forum.xojo.com/conversation/post/195536