I coach high school. Our team expectations include being at practice every day during the official season. We have a 3 strike policy. 3 unexcused absences results in removal from the team. Reasons for an absence to be excused and not count in those 3 include: family emergency, school sponsored internship (if limited in number). Examples of unexcused absenses: soccer practice, long term tutoring, studying, doctors appointments, etc. This teaches them to balance their time and only take on realistic responsibilities. If a kid needs extra time to study and misses track every week, they need to spend their time on school, track is clearly too much.
Kids can do whatever they want on the off season. If a kid wants to workout with a club coach off season, I'm not offended. I've only had 3 kids make that choice across all event groups over the past 8 years, the majority workout with the team during the off season, which was good enough for multiple state champions over the years (I'm in California).
Of course, we have multiple quality coaches on our staff to make that happen. I'd remind the OP that their kid's school sport is about more than just success at the sport. It's about teamwork, sportsmanship, etc., qualities that lying about skipping practice arent compatible with. If you really want your kid to do their own thing, there is nothing wrong with that, but be up front about it. Hopefully if the coach is bad at the coaching and just filling in, he will be willing to let your kid do their own workouts. If not, I'd encourage your kid to simply do club track, that's why it exists.