Yes, of course, you can, but my comment was meant to address the concerns of the parent. If you have side projects, you don't have to be afraid that they will criticize and judge you X-Factor style about them.
If the applicant has side projects, it's often easier to talk about them instead of day-job code, since they usually are more passionate about that, and they can talk about it more freely because they don't have to be afraid to (accidentally) spill company secrets. Side projects are not a must and I've had good conversations with applicants about their work projects, though more confidence to talk about them is something that comes with seniority in my experience.