Don't wait. Do what you can now without causing additional complications to your injury and you'll be stronger in the long term. Keep in mind that if you arn't benching, your press won't progress as well as if you were healthy and doing the full program. By the time you heal and can start benching, your upper body will be behind but that's fine.
Imagine you had started the program a year ago and then cracked a rib now... your bench would de-train while you recover and you'd have to catch it up with smart programming after you healed. Life happens to everyone and you shouldn't let an injury limitation derail everything.