It can be quite a hiking trip for an 8 year old. I guess my first question is whether they can physically do it. It can be heard, and painful. I think it would be unusual for an 8 year old to make the hike, but it depends on their stamina and attitude. As for booking places to stay, we did do that because then we knew we had a place to stay, and based on reviews, some assurance of the quality. We actually booked ours a few months in advance. That said, there are downsides. If we could do it again, we would have booked the places to stay a bit closer together. We used the Brierley guide stages and found them to be a bit more than we should have done in a day. If you don't book, you can stop when you need to. Allowing some time in the evening to meet other pilgrims would have been nice. Booking rooms in 2020 may be a good idea as they are expecting an increase in pilgrims with it being a holy year. My God be with you!

Contact Walks in Spain. Paul would be more than happy to give you recommendations.

My friend did the whole camino by herself and booked accommodation in dormitories each day. She transferred her back pack easily when she decided not to carry it. She indicated she felt very safe. End of August 2019 to Oct 9th 2019.

That all depends on the time of year, where you were planning on stopping, etc. There is not a firm answer that can be relied upon. You have to decide if you want the security of knowing you have a place to stay and where. The down side is that you may find yourself walking with others who do not plan to stop at that location, and you will become separated. Or you may have over-reached or under-reached your estimate of how far you were planning on walking each day and the accommodation is not where you would like it. When we walked, we opted for the security of having a place...and a place that we could research for quality. That said, some days we over-reached and should have stopped earlier. Either way it is a gamble...you just need to determine what is more important to you.