I am sorry for not replying sooner.
I was able to get it semi diagnosed and reassembled and it still ‘works’ the same as before but, unfortunately, it will need 1-2 parts before it will work for taking pictures. The blessing is, while praying about which part to buy and whether to buy it or not, the Lord provided a wonderful buy on a Nikon D800e. So, the Nikon D90 is not fixed yet but maybe sometime… 🙂