Service tax registration for export service

Hi,

I wanted to know that if an individual software professional is providing export service and the turnover is more than 9 lacs, do he have to register himself for the service tax?

As per my knowledge Export service is exempt from Service Tax. Do he has to register and claim exemption in every time?

Do he have to file return even though there is no service tax payable?

Is registration required even if the turnover is below Rs.10 lacs?

Thanks in advance