[Joe Carola]

I need to build a deck or balcony above my garage door, without any vertical supports (risk of having them banged up by car).

Dimensions are 108 inches width, and depth is 54".
Attaching a 4x4 post to each side of garage door, with bolts going clear through the cinderblock.
Then, attach (with bolts through) diagonally, a 2x8 to each side of the post (total of 4 diagonals - 2 on each post x 2 posts), at a somewhat steep angle. These would be the only supports.
Overhang (past the diagonals) will be about 15"
Joists (2x8) - spaced 16" to be attached with metal hangers to perpendicular floor beams
Or.... do i need to first attach a ledger and then attach the joists to the ledger?

Thanks for any help or guidance you may provide

Call an architect or engineer and have them figure it out. Then provide the plans to your building department for permits and inspections.