Again, thank you for continued help.
Problem solved - very simply, indeed. Problem was: As I said I was unable to install LR Classic after having downloaded the application. Reason why: Missing CreativeCloud on my computer.
I had expected CC to be bundled with LR, but that was not the case. Very simple and straightforward solution: Downloading and installing of CreativeCloud! Then BOTH my old LR Classic ver. 6.0 AND the new LR Classic ver. 9.2 became visible and available.
New question: What about use and payment of these programs? I thought I had purchased LR Classic, but as it seems it was CC. Does this mean that both versions of LR are equally available as long as I pay for the CC plan?
I feel I know LR version 6 quite well, but feel reluctant in abandoning it all together. There are reasons to believe that the new LR Classic contains prefereable improvements and features over ver. 6.0. But in case I should not feel content with the new version, the old version could come in handy.
What to do? Would it be possible for you to just give a short piece of advice on this?