Laptop cannot detect Kindle Fire HD 8.9 in Device Manager
Download and install the adb drivers from this link, then reboot your pc.


  
    Next installing the USB drivers for the Kindle from Amazon.
  


(Windows user) Uninstall the existing USB driver

If you are a Windows user who previously connected a Fire tablet without first enabling ADB, you will need to remove the existing USB device driver and force re-installation of the driver.


Connect your Fire tablet to the USB port on your development computer.
On the development computer, from the Start menu, right-click Computer, and then click Control Panel.
On the control panel page, then click Device Manager.
In the Device Manager window, expand Portable Devices.
Right-click the Fire device and then click Properties.
In the Properties window, on the Driver tab, click Uninstall, and then Confirm.
Unplug your Fire tablet from your computer.




Install the USB driver for Windows.

Perform the following steps if your development computer runs Windows.


You can directly download the USB driver from the following URL:

https://s3.amazonaws.com/android-sdk-manager/redist/kindle_fire_usb_driver.zip
Extract the zip folder into a new folder.
Open the new folder and run the executable file, which installs the driver.




Source:

https://developer.amazon.com/docs/fire-tablets/ft-set-up-your-kindle-fire-tablet-for-testing.html#windows-user-uninstall-the-existing-usb-driver

https://developer.amazon.com/docs/fire-tablets/ft-set-up-your-kindle-fire-tablet-for-testing.html#windows-user-install-the-usb-driver-for-windows