How boards should we get for a 9x9 deck?

Hello and thank you for your interest in Trex! Due to many unknown variables associated with deck builds Trex is unable to assist with material lists. For further assistance you may contact your local Lowes store at the lumber desk to discuss, or you may use a free online decking calculator tool, or feel free to reach out to a general contractor of your choosing. I hope this helps get you started. Thanks, - Trex Customer Care Team