Those prayer tables use 18° for Fajr, it is recommend to wait 10 to 20 minutes before starting Fajr salaat. Equally, complete sahur (imsak) (pre-dawn meal) 10 to 20 minutes Fajr time when using 15° table. And now finally, to answer your question, no where in the article did the mention of angle less than 9° come up. More @Wikipedia
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