I doubt you'd ever scramble jets to deal with a single confirmed small drone of the commercially available variety flown by hobbyists. In that case you'd tell the police, "go and find the owner on the ground, who can't be more than a few hundred meters away. "

But in this case you have several apparently concurrent or nearly concurrent overflights of nuclear power facilities at different ends of the country. So at the very least you're not dealing with a single small drone, and you're almost certainly not dealing with something small and commercially available. If you're being pranked by teenage stoners, they're teenage stoners with 9/11 hijacker levels of coordination.

So you have to at least suspect you might be dealing with a military grade drone. And indeed there were anecdotal reports of "winged" drones but god knows how reliable they were. Fundamentally you're dealing with some kind of unknown aircraft that is at least a fairly serious piece of hardware. And given that, and given the multiple concurrent incursions on successive nights and the sensitivity of the targets, I think you do scramble fighters, yeah.

And not because you're going to engage and fire on them over populated areas. But principally to 1) get a look at them with the radar and FLIR and try to positively ID them and 2) signal clearly to any state or non-state hostile actor that your Air defence forces are awake and are onto you and taking your activities seriously. I think in the US, post 9/11, fighters would've been airborne as soon as the pattern of reports from multiple power stations came in.