Fix version number to 2.9a0

wagtail/__init__.py

@@ -5,7 +5,7 @@ from wagtail.utils.version import get_semver_version, get_version
 
 # major.minor.patch.release.number
 # release must be one of alpha, beta, rc, or final
-VERSION = (2, 9, 0, 'rc', 1)
+VERSION = (2, 9, 0, 'alpha', 0)
 
 __version__ = get_version(VERSION)
 

wagtail/project_template/requirements.txt

@@ -1,2 +1,2 @@
 Django>=3.0,<3.1
-wagtail==2.9rc1
+wagtail==2.9a0