If you are talking about QV servers - you cannot because services that need to run the Qlik server for both v9 and v12 use the same ports. If you are talking about 'Desktop' - you can. I remember the trick was something like install it with different admin users.
Note: haven't done that myself, so you may want to hear some other opinions.
Why would you need version 9? You can load QVWs created in version 9 even on v12.
Believe you are referring to Desktop Client in which case you can, just follow the below:
In order to run multiple versions of QlikView Desktop on a single machine, please follow this procedure:
1. Uninstall prior version 2. Install QlikView Desktop v12 3. Copy the QV.exe file to a new, safe location 4. Uninstall QlikView Desktop v12 5. Install prior version Following this procedure, you end up with a working version 12 QV.exe, but the operating system treats the prior version as your primary version of QlikView.
You can reverse things here regarding versions as well, hopefully this is what you needed.
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