The solution to using App Inventor in your student's situation is to provide an old lap top that the students can share. You don't need a hammer to drive an nail; you can use a rock. You don't need a brush to paint a fence, you can use a rag. But it helps to have the right tools and a lap top won't ruin your student's eyes and make them think programming is drudgery and frustrating.
Like Alaqmar, I have tried using a cell phone; a disaster. Tried using a 10" tablet, better but still very unsatisfying. Moving from a cell to a small lap top is like letting a blind person see.
Have you tried using a cell phone? It can be done but would you want to if using the right tool makes the experience 1000 times better. Follow Alaqmar's advice, it is VERY difficult compared to a laptop.