It's enough space. Make sure you lift with the bar along the 8 foot plane, not perpendicular to it. I worry more about the space on the edges, but you should be fine. As Duke says, learn to miss. Don't have heroic efforts to save the bar by stepping into the lift, etc.
Also, forget the power rack. Get a nice set of squat stands like Ironmind sells (great for a small space- light, easily moved, and hold everything). If you have the budget, get a set of their spotting stands, too. Expensive, but again, easy to move and take apart.
The other squat racks you can get will take up more space on the platform. You can also get some squat stands that are independent of each other, but the Ironmind racks are more versatile.
In comeptitions, I've taken lifts to the edge of the platform to save them, and I've backpedalled to save lifts, too; I've almost run out of room on the 4 meter sq platform. In training, I never stepped off a platform. I almost have, but I should have dumped those weights for my own safety.
I used to train at a gym where there was a wall mirror behind us, and the mirror never broke through 15 years of lifters training in front of it.