I've got a Centos 7.2 desktop that is spamming the syslog server and also filling it's /var/log partition with constant messages :
kernel: ACPI: _SB_.PWRB: ACPI_NOTIFY_DEVICE_WAKE event
Can I disable ACPI messages / events or do I just need to filter these messages out in the syslog config?
Yes you can disable the acpid service, though I suspect this is a BIOS setting to do with WOL support - see if that's enabled and if so, and you don't need it, then disable WOL support.
As mentioned in my comment, add acpi=off to boot options in grub config. This doesn't resolve the issue itself but does answer the initial question I asked.