I would suggest you
- First update the existing setup to 9.9.4.
- Backup / export data
- Flash new image to (new) SD Card
- Install card, get system up and running (wifi etc).
- Update EmonCMS system (image is not on latest).
- Restore data (which will include dashboards etc (hopefully…)
By using a new card, you have a route back to where you were if something goes wrong.