The answer to this depends on what you intend to use as a master clock in your set up. MIDI Timecode (MTC) is an appriopriate solution for use with both Ableton Live and Kyma. When Ableton is sync'd via MTC its linear timeline is under control by MTC. Thus clips and loops will be properly synchronized. The project's tempo map (global tempo change markers and time signature changes) dictate how timecode is converted into bars and beats.
The challenge when using MTC with Ableton and Kyma is that neither is capable of generating MTC. Live is unusual in this regard as most DAWs fully support generating MTC. Alas Live does not. So you will need something else in your overall project setup to provide the MTC. There have been software utility applications available that offer MTC generation. Search the Internet to see what comes up. You might need to be creative though and do something like use the demo of another DAW that does offer MTC generation.
All of that is a traditional approach to synchronizing two or more sequencer using MTC. Kyma though has some powerful non-traditional tools available. Kyma's timeline has some interesting features that can be used to implement some of the same non-linear playback features often used with Live. One is markers, and they can be assigned to be invoked when Kyma receives a MIDI program changes. This means that you could, for example, have a Live MIDI clip send a program change to Kyma which would in turn cause the timeline to move to the corresponding marker, thereby controlling Kyma's timeline by which clips you trigger.
Kyma is also capable of doing things on-demand based on the arrival of a MIDI event. You might create an Ableton Live arrange track that has timed MIDI events sent to Kyma. Kyma would then react to those events, whether it be to cause the timeline to do different things, or simply within a single Kyma sound to do something like synchorize a sequencer or some control. Capytalk is very much your best friend here! In all of these scenarios Ableton is the timing master. This means that you can use any of Ableton's other synchronization options, like MIDI CK or Ableton link, to synchronize your modular, other external gear, or even other software running on your computer.
Your modular though by its very nature opens up some additional non-traditional ways to synchronize. It too could be patched so that discrete MIDI events trigger activity. Viewed this way then Kyma could become a powerful source for triggering modular activity.
There are some additina ideas on the old Tweaky page here: http://www.symbolicsound.com/cgi-bin/bin/view/How/SyncKymaBPMtoMidiSequenc