What will be the consequences if I select 9 leave from leave type and have only 7 leaves remaining in that type of leave?

Experience@ ZING HR:

After selecting date and then click on apply it would give you a message stating “maximum number of total leave day required is 7”

This would also differ for different organization and organizations policy.

To identify this point you need to check the Maximum/Minimum Leave Application Rule from the leave rule builder. This message will appear if selected date range exceeds the limit which is set in the Leave Rule Builder.