That is a great image! Even more so because i just spent over an hour looking for various images, comparing tire sizes, canister lengths etc, etc. I even managed to find the website of the maker of the truck and found truck's height, which was also quite helpful. And I was about to come here and write that to the best of my ability, the length of the the hq9 canister seems to be 7 meters. And since large missile for s300, which is 7,5 meter long, fits in a 8 meter long canister,
i was about to write that i guesstimate hq9 missile to be around 6,5 meters long.
This image corroborates my measurements, which is superb!
Also, it would mean that misssile diameter at its thickest is around 0,4 perhaps 0,45 meters. (i cant find high res enough image to be more precise there). But the missile's body gently tapers towards the radome (more gently than s300 missiles) and nearing the radome it could very well be little under 0,4 meters wide.
Here's another assumption, related to range.
Last development of 5v55 missile achieved 120 km range, and that was with 7 meter long missile, not much wider than hq9, back at the end of 1980s and beginning of 1990s. Then we had the early 48n6 missile, introducing a wider body 7,5 meters long. it achieved 150 km range. it was offered around 1992. but based on similar tech as late 5v55 variant. at the end of 1990s the improved 48n6 missile came, with it the system was quoted to have 195 km range. with s400 we saw further development of 48n6 missile and with it the system is usually quoted to reach 250 km.
Roughly speaking, if one was to use hq9 sized and styled missile and use late 5v55 tech with it, in early 90s one could expect range of around 100 km. (since half a meter longer and 5 cm wider 48n6 added 30 km over 5v55 using same tech level) Using similar progression of tech as the s300 missile families, one could expect late 1990s tech to improve that to around 130 km. Then using the progression that we saw come with s400 system, same missile might be able to reach some 162 km.
But it is important to note that this is merely a rough ballpark figure. So many more things influence range, and officialy quoted range itself is often subject to arbitrary decisions and interpretations, requirements etc.