We have upgraded a moodle instance from 2.8 to 2.9 as described in this place: https://docs.moodle.org/29/en/Upgrading
The course enrolment is working against an Active Directory and was working in Moodle 2.8.
The configuration hasn't changed. If we roll back to Moodle 2.8 everything is working as expected.
The configuration is just standard: No TLS, LDAPv3, cp1252 encoding.
We've also configured the user sync with the same options. This is working as expected.