hi
bug in ver 2.9 stabel
please fixed bug - hotspot could crash with 15 users
For me it will crush almost whole network 
Fast downgrade is the my solution .
im downgread after 3 day to 2.8.28
im not problem in the ver 2.8.28
please email to support@mikrotik.com with the description of your network and also include the support output file which is made after the Hotspot crashed, so we could fix that in future releases.