Is the word acredito the same in Brazilian and European Portuguese?

Yes

The spelling, meaning, and grammatical function of "acredito" are identical in both Brazilian and Continental Portuguese. The only difference is pronunciation:

• Brazilian Portuguese: The vowels are more "open" and the articulation is more distinct. The rhythm is more melodic, and the unstressed syllables are clearly pronounced.
• Continental Portuguese: The vowels are more "closed" or reduced. Unstressed vowels tend to be swallowed or minimized, giving the word a more "clipped" or staccato sound.

Brazilian Portuguese Examples

1. Eu acredito que vai chover hoje. (I believe it is going to rain today.)
2. Eu não acredito que você fez isso! (I can't believe you did that!)
3. Eu acredito plenamente em você. (I believe in you completely.)
4. Eu acredito que a reunião já acabou. (I believe the meeting is already over.)
5. Eu não acredito em fantasmas. (I don't believe in ghosts.)

Portuguese Examples

1. Acredito que venha a chover hoje. (I believe it is going to rain today.)
2. Não acredito que tenhas feito isso! (I can't believe you did that!)
3. Creio que a reunião tenha terminado. (I believe the meeting has ended.)
4. Acredito que o prazo termine amanhã. (I believe the deadline ends tomorrow.)
5. Não acredito em coisas sem sentido. (I don't believe in things without sense.)