Is it morally right to finish work early?

I work for a shop for which I am the sole paid member of staff. I live 13 miles away and rely on my partner to take me home from work. Very occionaly my partner cannont collect me. Is it morally right to close the shop either an hour or half an hour early to catch a bus. Alternatively I have to hang around for an hour after closing to wait for the next one. I am also usually at work unpaid an hour or half an hour before opening to get things done, so I think I am entitled to take this time off occasionaly.