To control the IanniX transport based on startingstopping the Ableton transport you could use Max for Live to send the appropriate OSC messages to IanniX when the Ableton transport is started and stopped.
Of course this would not be a complete solution of syncing.
I’ve been recently helping with IanniX development and one thing I’d like to add is better syncing capabilities to external applications. What features would you like? It seems to me that having IanniX capable of acting as an MMC and MTC slave & master would be a good solution. IanniX i actually currently has quite limited MIDI features, but these will need to be enhanced for it to play nicely with widely used music tools.