sm_studio, you can use CD Track markers and ISRCs in a 96k montage just like in a 44.1. That’s the easiest way to do this if you already have a 96k montage. Put in the CD track markers and all of the ISRCs (using the wizard or manually), and then render individual 96k files from that montage using the selection Regions/CD Tracks, and using the ISRC factory preset in the file format metadata section in the render dialog. That’s the easy way to do this and get the right ISRC into each of the individual rendered files.
If you want to add the ISRC directly to an existing audio file instead, open the audio file, go to the metadata tab, and select the ISRC factory preset at the bottom. Then go to the AXML tab. In that block of text is an ISRC variable: @ISRC@. Replace that whole variable “@ISRC@” (including the @) with your real ISRC code. Only remove the part that says @ISRC@. Then go to the ID3 tab (ID3v2). Replace the whole “@ISRC@” variable there with your real ISRC code. Then save the audio file.
Just be aware that until the next Wavelab update the BWF ISRC (the AXML part of this) will not be totally compatible with some other programs.