Essential Elements (https://www.amazon.com/Essential-Elements-2000-Comprehensive-Clarinet/dp/0634003143/ref=pd_lpo_1?pd_rd_i=0634003143&psc=1) is the book I use for teaching clarinet in my regular classes.  It is required for this book because of copyright issues.  If I show a book on Outschool, it cannot be a book that the student does not own.  Therefore, it is required, but rest assured that it is used in many bands in the U.S. and is used in future classes with me should your child continue with me as a student.  

New to clarinet students should have strength 2 reeds to start.  https://www.amazon.com/Rico-Bb-Clarinet-Reeds-Pack/dp/B01MQJV8NI/ref=asc_df_B01MQJV8NI/?tag=hyprod-20&linkCode=df0&hvadid=532852636045&hvpos=&hvnetw=g&hvrand=12761395855025096152&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9012005&hvtargid=pla-1435477127455&psc=1&m=ATVPDKIKX0DER

Appropriate strength reeds to each individual student , if not new beginner. 
 A music stand is useful, but not required.  If you have a place to prop the book up, that will work.  (Pianos have music stands built in, so they work as well.)

Practice is not required, but would be a good habit to establish at this point.  Small pieces only require minutes per day, and the mouth is not strong enough to for much practice yet, either.  Still, it is good to get started building that embouchure.  

Space required:  I know most people have limited space near an internet connection, so I will limit movements to a 6 square foot area.  The Learner must be able to march 6 feet safely in any direction without obstruction.