There have been significant scalability improvements in that time (9.2, 9.5). There also have been lots of smaller improvements in single threaded performance i

There have been significant scalability improvements in that time (9.2, 9.5). There also have been lots of smaller improvements in single threaded performance in general, leading to rather noticeable aggregate improvements. That's all for the cases where the same query plan is used in 9.0 and 9.5 - the differences where new type of plans (say index only scans) are often very large. In short: yes.