Yes, you can use Red Dot for 9mm. See the 1992 Hecules pamphlet here:
http://www.castpics.net/LoadData/Fre...M/Alliant.html
Alliant is the successor company that now owns the Hercules (renamed Alliant) line. The current Alliant website has been trimmed of many old loads, as they have added newer powders. But the old Hercules line of Red and Green Dots, Unique, Bullseye, etc. are still sold in huge sales volumes and work just fine. Blue Dot is a magnum shotshell powder and can be used in 9mm 147 grn. bullet loads, but you wont try that until later. Everyone says Blue Dot is dirty, but that has more to do with the pressure needed to fully burn that slow powder (you would only use it for heavy bullet loads).
Note that the COAL, as everyone else is telling you, are longer than you stated.
One more thing: If you have Red Dot on hand now, or are going to use it for shotshell loads too, great. However, Power Pistol is a newer Alliant pistol powder that is more perfectly suited to 9mm and 40 SW. But, you would not use Power Pistol in shotshells. Power Pistol meters better than the flake/disc shotshell powders for pistol loads. So, if you are only going to load 9mm, look for Power Pistol. Bullseye is another very good Alliant Pistol powder.