There was a confirmed covid case at work, they came into work on a holiday and i went the next day just after 9 and the office was cleaned. how possible would it be to become exposed?

Very low: Although not 100 percent it is very unlikely that you will catch the virus. Typically needs to be spread by contact with person either coughing or sneezing. I am still practicing full time ER and I am unaware of any indirect spread in my facility. Nothing is 100 percent and sometimes people do catch disease from toilet seats, but less likely.

COVID 19: If area was well cleaned the risk would be VERY low. This individual would no longer have been there for direct droplet transmission and well cleaned surfaces should take care of of contact contamination.