Purchase bills not up loaded

GSTR 1 IS ONLY FOR THE SUPPLIES OUTWARD (SALES) 

If I am understanding well your question you want to ask whether your supplier can include the previous FY Outward Invoices in GSTR-1 of current FY 2018-19 or not so that you can claim ITC.

Then, answer is Yes. Your supplier can update the missing Outward Invoices in GSTR-1 for FY 2017-18 before filling return for the month of September 2018 or Annual return filling whichever is earlier. As per the current situation Annual return Filling 
Form is not available then last date before filling return for September 2018.