Update v0.8-to-v0.9-upgrade.md (#1209)

Updates the v0.8-to-v0.9-upgrade.md to include the information about dropping annotations in v0.9,

Author: am357

docs/wiki/upgrades/v0.8-to-v0.9-upgrade.md

@@ -30,7 +30,30 @@
 
 ### Breaking behavioral changes
 
-N/A
+In version v.9.0, as a result of deprecating `ionValue` property in `ExprValue` and introduction of the substitute method `ExprValue.toIonValue(ion: IonSystem)` in Kotlin, and `ExprValueKt.toIonValue(value: ExprValue, ion: IonSystem)` in Java.
+Ion annotation will get elided from the provided Ion values in identity evaluations:
+
+#### Example
+```Kotlin
+val query = `annotation::1`
+
+/* Prior to v0.9 
+
+  ExprValue: IonExprValue
+  ionValue: annotation::1
+
+*/
+
+/* After v0.9
+
+  ExprValue: IntExprValue
+  toIonValue: 1
+
+*/
+```
+
+_**Note: Support for Ion annotations will get added back once the work related to finalizing the specification as an RFC is completed. See [partiql-spec/issues/63](
+https://github.com/partiql/partiql-spec/issues/63) for more details.**_
 
 ### Breaking API changes
 * Removes the deprecated V0 AST in the codebase.