This is why web development gets tough. Each browser plays differently with the code now because browser developers of (firefox,chrome,etc...) think everyone should adapt to their way how code gets handled. Web developers now are forced to add additional coding to support each browser & things can get ugly if not properly done.
My school also uses blackboard and they state in bold that IE9 is not recommended as it causes issues.
Web Designer & Developer @ Tinyminute.com / Gamer / Apple Geek / I.T. Guy / MacBook Pro User