I have been back and forth with Meraki on this. Originally, Meraki told me they added the feature (see below). After banging my head against the wall for days, I could not get it to work. I opened a ticket and Meraki told me the feature was not yet supported and still under development. That was in November. It has been 7 months and it is still not supported.
Bill
From: Systems Manager <sm-wish@meraki.com>
Date: Tuesday, October 30, 2018 at 9:11 AM
Subject: Re: A wish to Meraki from Bill Bates
Hi Bill,
Just wanted to let you know that in part thanks to your request, we have now made the Education payload available for macOS devices on the Settings page.
One "gotcha" with this payload on macOS is that it needs to be sent over the user channel, so you will need to have separate profiles for iOS and macOS, with the macOS one being of type User profile (Apple).
On Fri, Oct 26, 2018 at 2:11 PM Meraki <wish-noreply@meraki.com> wrote:
wish: Apple has released the Classroom app for macOS. Currently, in Meraki Systems Manager, the Education payload is only configurable with iOS. Please add the Education payload to macOS so we can use Apple Classroom on our teacher's laptops.