"oo" can stand for "ole" in spoken Finnish. The sentence decides its meaning.
Ei oo, se on ihan lähellä. - No, it's really close.
oo here: be - spoken form of 'ole'; 'ei oo' = isn't
Written Finnish: Ei ole, se on aivan lähellä.
Mä en oo ikinä syöny mämmii. - I've never eaten mämmi.
oo here: have - spoken 'ole'
Written Finnish: Minä en ole ikinä syönyt mämmiä.
Tota... mä en oo ihan varma. - Um... I'm not quite sure.
oo here: be - spoken 'ole'
Written Finnish: Tuota... minä en ole ihan varma.
Sitä paitsi meil ei oo ees aikaa. - Besides, we don't even have time.
oo here: have - spoken 'ole'
Written Finnish: Sitä paitsi meillä ei ole edes aikaa.
Ei se niin justiinsa oo. - It doesn't have to be that exact.
oo here: be - spoken 'ole'
Written Finnish: Ei se niin tarkkaa ole.
Mul ei oo aikaa harrastuksille. - I don't have time for hobbies.
oo here: have - spoken 'ole'
Written Finnish: Minulla ei ole aikaa harrastuksille.
Spoken and written Finnish are different registers. The examples show how "oo" is used here and pair it with the written sentence. Learn the meaning in context rather than replacing every occurrence of a word.