Our garage door has some cracks in it from the kids crashing into it with their bikes. It is a wooden, non-insulated door. There are no thru holes, just some "star bursts" from the Evel Knievels!
A buddy of mine builds boats. He suggested a technique used in that trade of using two part epoxy with wood flour (sort of a fine graned saw dust) that would be trowled into place and then sanded and painted.
What type of wood door? Smooth outer skin, or the traditional panels held in rails and styles? If the latter, the panels can sometimes be replaced. If you are lucky, the molding on inside is removable to free the panel. If the panels ride in a kerf in the solid rails, you either have to disassemble the door section to get it loose, or carve out enough of the inside rail to free the panel, and then fake it with trim afterward. If the panel is captive, I'd enlist your buddy the boat builder's help, but with the addition of a layer of glas fabric and/or a brace plate on the 'hidden' inside of the panel. I assume the door is painted, not stained? If so, rather than fussy epoxy for the surface prep, I'd use automotive Bondo kit. Much easier for a non-pro to work, and holds paint better than epoxy does.
As to the kids- maybe velcro a strip of that ensolite stuff they use as dock bumpers, say between axle height of smallest bike, and forehead height (while mounted) of tallest kid? :^/ It's just a garage door, after all, and in a few years you will treasure those scuff mark momentoes of their formative years. expects a house with kids to be pristine.
HomeOwnersHub website is not affiliated with any of the manufacturers or service providers discussed here.
All logos and trade names are the property of their respective owners.