There are many changes you can implement Venky. This is my take on it.
1. First Step upgrade with as it is. Means if you upgrade your environment without any changes to the apps( no edits to the apps). So you will have all your apps with version 11.20. This is how you do but phaneendra.kunche correct if i am wrong. Empty your dev server means clean up everything in there. Now clone your production server and paste it in Dev server. Now you have all the apps which you have listed above. Now upgrade your dev server to 11.20. and make sure the QEMC will have all the schedules for the tasks which are there in the version 9 as in production system.
2. Once the dev server with all your apps and new version ready along with QEMC have all the tasks to run. Run them over couple of weekends and see if there are any issues ( because version 11 and 9 script handling is totally different)
3. After it runs successfully, now take one complicated app for each department and ask your business users to do visual testing. i mean makki ka makki testing. compare your version 9 apps to version 11 apps visually ( like selections, input boxes & charts behaviour.)
4. if above step is successful , now you have a environment with version 11 upgraded and working condition which you can rely on. Now its time to work on the apps.
5. identify the base QVDs, create separate extracts for them so that they can be consumbed by all apps. follow qliktech folder structure. reduce redundancy of QVD builds.
6. follow 3 tier architecture
7. Find areas where you can combine datamodels together so they can used for multiple apps.
8. Now when doing front there are plenty of changes in version 9 we don't have hide and enable functionality for dimensions and expressions leverage that option. Section access can be anywhere in the script. We don't have dimensional limits back then now you have in 11.20 so remove any ranking or aggr functions.
9. follow qliktech best practices for developing front end apps
planing sprint wise is little tricky.We need understand about the entire environment. then we can plan accordingly. Do the client as any in house developers. Ask them to give you Knowledge transfer. And also get a second opinion from phaneendra.kunche
The qvws should move with little or no change.
The only significant change I can think of between 9 and 11.2 is the removal of the OnActive/Deactivate Object triggers. Those were removed in V11. If yo have any apps using those, you will have to replace them with another solution.
Do you need to migrate the job schedules as well? I believe there was a tool to migrate schedule from V9 to V10, and then V10 to V11, but I don't think directly from V9 to V11. Perhaps someone else will recall.