Clock sync should work for keeping the BB and looper in time, but the Boss can only send / accept CC messages in ranges 1-31 and 64-95. This is a blocker if you wish to synchronise BB functions such as fills and transitions to different parts with the looper.
The only messages that BB can send / receive in those ranges are
Tempo Increment (NewTmpo = Tempo + value)
Tempo Decrement (NewTmpo = Tempo - value)
0: Return to normal mode 1-127: Go to half time mode
0: Return to normal mode 1-127: Go to double time mode
You would need a device in between the BB and looper that could map CC values to other values, such as the Midi Event Processor
Or use a master device or app (like OnSong) to control both devices.