ha llegado ... he ofrecido

Question

Do I understand correctly that this sentence implies that it took today or even a short time ago?

Answer

Hola Emanuel
In this sentence:

Cuando mi novio ha llegado a casa, yo le he ofrecido un café.
When my boyfriend arrived home, I offered him a coffee.

using the present perfect implies that the speaker is not being precise about when he arrived and when she offered the coffee. It also normally implies as you say that it is something that has happened recently (today, in the last few hours) and it feels like it is still connected to the moment of speaking.
Saludos
Inma