UPDATE:
Word to the wise for PowerSchool users:
1) PowerSchool must have a SSL cert applied, contact PS for more assistance. (Using GoDaddy was a breeze.)
2) PowerSchool must have the following services enabled to SSL over Port 443 after cert is added:
PowerSchool Configuration - External Access
PowerSchool Configuration - Internal Access
PowerTeacher Gradebook Settings - External Access
Find settings at: Start Page > System Administrator > System Settings > Edit Global Server Settings
3) In Apple School Manager, set the URL to begin with "HTTPS://" then followed by the baseline URL.
For example: https://powerschool.districtname.org
4) Copy your Client ID and Client Secret exactly; watch for spaces at beginning or end when you copy, don't use them or you'll get an error.
If all goes right initially, you should get this notification:

The issue I am trying to wrangle now is Classes. It seems that the classes will not appear from PS until the first day of the term. Changing the dates on the term is not an option in PS since it is tied to student attendance. It would be nice to see this information before 8pm on the first day of school when this date will finally sync in from PS to ASM.
An issue we have is that any user that is assigned to one or more schools is being brought over as a teacher, whereas those that are assigned to only District Office are not being brought over at all. So school secretaries, food service workers, administrators, principals, custodians, maintenance workers, etc. are all being brought into ASM as Instructors. This is causing lots of confusion and will be an ongoing problem because there is no easy way to differentiate who we need to send ASM login info to.
Do those people need access to ASM? Only our tech team has access to ASM at this point. And we don't give the teachers their ASM apple id's since they all have an apple ID set with their district account. The accounts are matched up when they are brought into our MDM for use with Classroom.
How often does ASM sync data from PowerSchool?
Every 24 hours - but there is no way to adjust the time. For us it happens at about 8pm every night.
By any chance does anyone have hosted powerschool successfully syncing with ASM?
Was anyone able to get PS to sync with ASM? We are PS hosted, but are not able to connect. All the info is correct (multiple plugins use the same base URL we are giving ASM, and I know the ID/Secret are correct).
@ahunternaf Were you able to determine why your PS hosted wouldn't connect ASM? We just switched to PS hosted, installed the plugin, but it will not connect for us either.