A lot of times the professors' hands are tied because of funding. You might be the perfect fit for the lab, but if the professor can't fund you and you don't have your own funding, they may not be able to take you.
You can ask him when does he expect to hear back from that particular grant. If this is the lab you have your heart set on, and you are willing to take the risk, you can strike a deal with the professor. Ask if there is money to fund your first year, and you will apply to fellowships so you can fund the rest of your program. I have friends who made similar arrangements with their advisors.
