1)Is it possible to click "Confirm Adjustment" without doing SPDD Adjustment ( Its for traing system )?
Yes you can. If you do so then you will lose the modifications done to the ABAP objects mentioned in Tx SPDD. It says that there is one ABAP object that needs adjustment.
2)In the Support pack upgrade phase, Can i resume my process from where I stopped once close the screen?
Yes.
3) Is it possible to revert the changes if get error while doing SPAM? Like My previous version is 8. I am doing for 16. If get error while doing 16, Whether can i revert it to 8?
Yes. You need to restore the backup taken before the patching.
Regards
RB