Did you try to open support ticket?
Yes I have. Any idea about backward compatiability from 9.0 to 8.7.
You may already have an answer for this one, but you will lose your incidents when you upgrade from 8.7 (probably 8.6 patch 1) to 9.0. If there are specific incidents you want to preserve, you can put them in a case. That information will be preserved through upgrade.
Hope this helps.