I have not done this myself but you can convert the FastAI model into Pytorch model and then convert the Pytorch model to a Tensorflow you can then use that model for android development, If you want to use Tensorflow lite you can easily convert Tensorflow model into a Tensorflow lite
Here are some that will help you achieve what you are looking for:
Fastai to Pytorch:
Try this first: Saving fastai model as a pytorch model
If the above one did not worked then see the link below:
https://mc.ai/convert-fast-ai-trained-image-classification-model-to-ios-app-via-onnx-and-apple-core-ml/
The link goes through how to convert a FastAI model into a CoreML Model to use it for iOS development. Just following the instruction of getting the Pytorch model
Then PyTorch to Tensorflow: