chore(build): add dotnot 9 to prerequisite check (aws#32158)

### Issue # (if applicable)

Closes aws#32282.

### Reason for this change
.NET 9 is now out: https://devblogs.microsoft.com/dotnet/announcing-dotnet-9

scripts/check-build-prerequisites.sh

@@ -127,7 +127,7 @@ app_min="6.0.100"
 check_which $app $app_min
 app_v=$(${app} --list-sdks)
 echo -e "Checking dotnet version... \c"
-if [ $(echo $app_v | grep -c -E "[678]\.[0-9]+\.[0-9]+") -eq 1 ]
+if [ $(echo $app_v | grep -c -E "[6789]\.[0-9]+\.[0-9]+") -eq 1 ]
 then
     echo "Ok"
 else