The cost to build a 9' x 12' deck that is elevated 9' can vary significantly depending on your location, materials, and whether you hire a professional. On average, you can expect to pay between $25 to $50 per square foot for a basic deck, which would put your project in the range of $2,700 to $6,000.
Since the deck is elevated, you may need additional support, which can increase costs. If you require a ledger board to attach the deck to your house, that can also add to the expense, especially if structural work is needed. Adding a privacy wall will also increase material and labor costs, so consider budgeting an extra $500 to $1,500 for that feature.
It's highly recommended to hire a licensed contractor for this type of project, especially due to the height and structural considerations. They can ensure that everything meets local building codes and safety standards.
Your next step should be to get 2-3 local quotes on Handyman.com to compare prices and services.