I'm going from HEL to ATH on May 30. The direct flight (with Blue1) leaves in the afternoon, but I would like to leave in the morning. One option is connecting in ZRH, with a long stop over, 8h35m btw flights. Will that give me enough time to visit the city?

HEL-ZRH: arriving 12:00 pm (SWISS 4791, operated by Blue1)
ZRH-ATH: leaving 8:35pm (SWISS 1842)

When would I get into the city, and when would I need to leave to make my next flight? Is there enough time to have a quick look and a cup of coffee, maybe a meal?