Yes, there is an SDR app available for Fire OS, called SDR Touch. It allows users to transform their Android device into a powerful SDR receiver.
Here are some of the features of SDR Touch:
• Compatible with all popular SDR receivers, such as RTL-SDR, Airspy, SDRPlay, HackRF, BladeRF, and Funcube Dongle.
• Supports multiple simultaneous demodulators and receivers, with frequency shifting from one tuning range to the next with a single click.
• Includes both a classic waterfall and a modern SDR waveform display.
• Automatically stores and loads your favorites for easy reuse.
• Automatically stores and loads your tuning settings.
• Runs in the background so you can use it while multitasking.
You can find out more about SDR Touch and download the app here: https://play.google.com/store/apps/details?id=com.febooti.sdrtouch&hl=en_US
I hope this helps!