No, he could not call the police. A tree fell on his phone line and disconnected his house.

And his parents did notify the police, but the police were, A: completely incredulous, B: completely incompetent and uninterested. They came and knocked on the door, but Kevin was still scared and confused and was hiding under his parents bed the whole time. The cop just gave up and left.

Source: I watched the movie again... and I am going to do so this year along with a Die Hard trilogy (I never watched the third movie) marathon.