Can I use the MIDI cable for the DIN SYNC?

Yes. If you use it for DIN SYNC, please use the MIDI cable with all 5 pins wired.
For details, see "Synchronizing the unit and an external DIN SYNC compatible device to play" in the Operating Instructions.
You can download the Operating Instructions from the Pioneer DJ support page
https://www.pioneerdj.com/en/support/documents/production/toraiz-squid/.