I wanted to know about the EWS certificate for CAT i have applied for it but not received yet and this the first time applying for it so i dont have any older one can i fill the form with the undertaking provided on their site

fill the form with general Category and then edit into EWS when the correction form site open 👍

Fill the form with a valid acknowledgement of you applying for the EWS form.
Another suggestion: Most likely the CAT form will get extended and they will announce it before 15 Sep, so if you feel you might get the certificate before the deadline you may wait. Again this depends on when your form will most likely be released.