When I was a kid they formed our basement and the morning of the pour the guy bringing the form oil didn't show, but the concrete truck's sure did. We still have wood stuck in places on the walls.
the osb will work fine just mebbe reinforce it on the out side with some strapping or framing lumber or stake, backfill and leave in place. Any sold sheet wood will work if thick enough.
When the contractor did my shop floor it was a 24"×30" thickened edge he used 2" ridged foam board with 2×6 bracing and a crazy amount of pegs/bracing, nice thing was when it set the slab was insulated and no heavy forms to remove and clean