It is all about the condition of the ears. Both my children tolerated their first flights just fine. Then, the younger one burst out crying before we reached 2,000 feet, and could not be quieted. He had an ear blockage, and could not compensate, so very painful. End of flight, returned to the field and landed. That was the only 'event' we had with our two, and I cruised as high as 12,500 for hours. They are both in their 50's now. It is wise to plan your descent shallow, as they tend to be sleepy due to the altitude, and less inclined to move their jaws, which improves equalization. My cruise descent was 300 FPM, starting way out, with no decrease in manifold pressure/RPM to recover the speed lost on climb out. From 9,000 feet to sea level, that is 30 minutes out, but my actual target altitude is pattern altitude or FAF, whichever is appropriate. The higher air speeds which this technique produces helps fit in with the big guys at the larger airports, so a win on many levels.
I did not fly with the kids if they had a cold, commercial or my own plane, if the Eustachian tubes clogged at altitude, there is no option of staying there until they are OK.
PS.... The seat belts were always on, throughout the flight. I have experienced singular clear air turbulence events at altitude that were violent, presumably from crossing a vortex from heavy jet at much higher altitude, he could have been 10 minutes ahead of us, equals 20 miles, and several thousand feet higher. We did not see him, ATC did not give us a call out for his passing. This has happened 2 times so should be anticipated on every flight.