Update default TWRP branch to android-9.0

omni-default.xml

@@ -12,7 +12,7 @@
   <!-- OmniROM Projects -->
   <project path="android" name="android" remote="omnirom" revision="android-7.1" />
 
-  <project path="bootable/recovery" name="android_bootable_recovery" remote="omnirom" revision="android-8.1" groups="pdk-cw-fs"/>
+  <project path="bootable/recovery" name="android_bootable_recovery" remote="omnirom" revision="android-9.0" groups="pdk-cw-fs"/>
 
   <project path="external/busybox" name="android_external_busybox" remote="omnirom" revision="android-7.1" />
   <project path="external/exfat" name="android_external_exfat" remote="omnirom" revision="android-7.1" />