I think it is obvious, that you can't compare this 55 min low budget TV film with standard high budget Hollywood movies regarding to production standards. But there is more about a film than production standards.
It is a nice and sweet film mostly for middle aged kids but also for adults who have an open mind.
The location of the film is portrayed as a rather poor area. The life of the kids is obviously not too much filled up with obvious beauty and a wonderful nature in the surroundings. So, the circumstances are not really supportive for the well being of the kids, specially in the future.
The basic idea is (in my humble view), that even in not so good circumstances, You can find beauty, mysteries and something which leads you to a meaningful life by living YOUR life. Just open your eyes (and be open, because there is more about life). Perhaps it is also about appreciating those little nice things and people which / who are supporting you and caring for you.
The substitute teacher (wonderfully and cute played by Amanda Plummer) is only the katalysator or cristalization point for the kids to recognize this (Don't want to write more about the content...don't want to spoil the content).
You can't expect a philosophical deep meaning film. But it is not meant to be. But it is definitly not a waste of time. It can't be, because at least Amanda Plummer is always worth to be watched in a movie. And the meaning of the film is very warm hearted. The film was produced 32 years ago (it is 2020 now). And it is sad to see, how degenerated the film industry has become since.
BTW.: The film is from 1988 and not from 1990 !