#List vms
VBoxManage list vms

#get status of time sync
VBoxManage getextradata <vm-name> VBoxInternal/Devices/VMMDev/0/Config/GetHostTimeDisabled 

#NOTE: Make sure to restart the VM after changing these settings.

#disable time sync
VBoxManage setextradata <vm-name> VBoxInternal/Devices/VMMDev/0/Config/GetHostTimeDisabled 1

#enable time sync
VBoxManage setextradata <vm-name> VBoxInternal/Devices/VMMDev/0/Config/GetHostTimeDisabled 0