yes using it in combination with libsoundfile is a good idea, we are planing to have an ofSoundFile class for next release that will do just that.
some time ago i started an ofBasicSoundPlayer: https://github.com/arturoc/openFrameworks/blob/feature-ofSoundRefactoring/libs/openFrameworks/sound/ofBasicSoundPlayer.cpp that uses ofSoundStream + libsndfile + ofSoundBuffer. you can probably use it with 0.9 with minor changes. if you want really tight control over the time, (sub buffer size) the you probably want to get the sound on an ofSoundBuffer and send it to the sound card manually but the code to load a sound file onto an ofSoundBuffer should be the same
