IGST Calculation

We are a bangalore based company and have taken a works contract in bangalore.

Our customers GST Registration number is Orissa Based and I have to do the billing for Orissa address but I am doing the work for there bangalore office.

In this scenario I have to charge my customer IGST (18%) or SGST+CGST (9%+9%)

And also can i claim input credit on materials purchased in Bangalore if I charge IGST.

Please Help.