SB: Kiam, you're a workhorse. I eat breakfast at 9:00, and you've already put in two hours of work. KL: Oh, I've had breakfast at 9:00. But it was always because I got so absorbed in my work I forgot to eat.
In this case could KL have answered "Oh, I have breakfast at 9.00"as it seems to be a habit .In term of meaning what does bring the use of present perfect(up to now I have taken breakfast at 9 but that habit can change)