Dear Amit
We can mention both. Normally we can get confirmed only at the time of receiving the pay sheet from contractors. During October, if you have the confirmed list that the individual will not return for duty in next month then you can mention his name in october return itself. Otherwise, if you cannot get confirmation about whether the worker will come and join on october or not, then you can keep pending during september and show his name in October month Form 10.
Hope you have understood the concept. In the Form X you have to give the date of leaving service. That can be for any date previous to that return filing month. In the first week of Nov you might have prepared and submitted alongwith Form V & X, in which you can even give Oct as well as Sep and even the long absented workmen after giving final, you can show their date of leaving service as their last working day. Hence you can show their names in this return with Last working day for the worker i.e., in Aug or July or June.
Hope you have understood the concept of Form X.
All the best