Biopsy is scheduled but - is it possible for ugly mole that has grown slightly with some colour change to be benign? no pain, oozing, bleeding, itch.

Possible: While anything is possible it is better to be safe than sorry . If it is getting bigger and has some color changing- better to remove it and see what it is.

Yes: Of course it can be benign, not every mole that shows some changes is malignant on the otherhand changes in a mole are a warning sign of some potential malignant changes. But why take a chance since melanoma can be deadly. That is why a biopsy is the right thing to do.