I had a back injury in 2004 that ended my stint as a competitive cyclist. Despite PT and staying active in all the "right" ways, my back nagged me for years. It wasn't until I started kayaking 2 years ago that my back problems went completely away. The use of my core in this sport developed the strength and flexibility I needed, without even knowing it! I now am free from pain and stiffness.
I do have a troublesome left knee that has greatly reduced my ski time this season. I did the necessary PT and am in the gym, continuing to strengthen the supporting muscles. When I did ski this year, I found that I too had lost muscle memory, and had to think about everything I was doing. It wasn't really that fun because I couldn't relax and let go. I got frustrated.
After talking to several people, and taking a lesson, I decided to take up telemark skiing. It is strengthening the same supporting muscles in my legs that I work on in the gym. Because I'm learning new movements, I have to develop muscle memory all over again. Although the process is much slower than rebuilding my alpine skills, I think the long term benefits are worth it, and now I have a real excuse to look like a dork on skis!
I can now relax and laugh at myself because I'm starting anew, without the pressure to get back to where I was on alpine equipment.
So, perhaps you might want to think about taking up an activity that will aid in strengthening your core and back, and allow you to have fun in the process. When you get back on skis next year, ski with your 9-year-old and focus on skill-building together. Above all, go easy on yourself. We do this for fun. Sometimes injuries and life gets in the way. When I get frustrated on the mountain, I stop and remind myself to take in the scenery and be thankful that I'm just out there.