There may or may not be a actual picture of the clock here but looks okay to me.
Looks he removed an off-the-shelf clock from its original case, and partially remounted the pieces in an equipment case.
The one PCB, with the ribbon cable leading to the display, looks commercial. And the other PCB, you can see it's the width of the original case (based on the width of the LED panel). You can just make out a cluster of dome-style switches on it. Finally, it's clearly AC powered, but has the 9VDC battery-backup typical of commercial clocks.
So he didn't really "build" a clock, not by my definition. He merely put the internals on display. Still, for a 14 year old, it shows a healthy inquisitiveness that can lead to greater things.
Though if I had encountered this device out of context, without knowing who created it and why, I'm afraid I can see how this could be considered HIGHLY suspect. Because a terrorist typically isn't going to build a clock or timer from scratch. They're just going to repurpose some consumer product, doesn't matter whether it counts up or down, it can still be triggered by the alarm. And this is, in fact, a repurposed consumer product. That it might be repurposed for education could be a distinction lost on a layman adult, not realizing that it would be ridiculous to use an oversized, AC powered product for a bomb. And that it might be viewed as repurposed for destruction could be lost on a 14 year old.
Hopefully all involved parties learned some good lessons from this. Are willing to admit mistakes made out of both prejudice and naivety, and apologize. Then fully move on.