Macs can natively support up to 24/96, played through iTunes or other software. However, without a couple settings tweaks, audio files with resolution higher than 16-bit/44.1kHz will automatically be downsampled to that resolution. So the first thing you need to do is set your sound output to 24/96. To do so, open Audio MIDI Setup, found in /Applications/Utilities. Select the desired output on the left, and then change the settings in the Format section on the right to 96000.0 kHz and 2ch-24bit.