Sorry, I couldn't find pricing data for that day. The closing price for Bitcoin (BTC) in terms of EUR on September 8, 2017 was 3,515.46. It was down 8.2% for the day. The latest price is 105,047.67.
DATE
OPEN
HIGH
LOW
CLOSE
September 08 2017
3,828.38
—
—
3,515.46
Daily pricing data for Bitcoin dates back to 7/14/2010, and may be incomplete.