I've had my first sugar glider ,Bear , for one year already and he's not very playful. During this first year a lot has gone on and I did not get to play with him a lot, but whenever i did it was always impossible to find an area with no danger! Lately I've been trying to play with him a lot more, yet every time I open the cage he hides behind his wheel! I have to grab him to let him out and even then he always is stuck in one place and poops out of fear or immediately runs under something to hide.
I don't know what to do! I really want to let him out to fly around the house! But what if he goes under wires or downstairs or in the kitchen!! And what do I do to help him become less afraid??
Thank You!!!

Unfortunately it's not really safe to let him loose in the house, especially if you're not bonded with him yet. Chasing him around the cage to grab him is probably scaring him (as evidenced from him hiding). That's probably setting back your progress wth him, to be honest.

How have you tried working with him over the last year so far? More info would be helpful so we don't give you advice you've already tried... But...

To enjoy out-of-cage time with your glider, you should look into getting a mesh bug tent (Sansbug is a popular brand). These pop up tents provide a safe place for your glider to explore while still being forced to be close to you. He'll climb you and learn you are safe. Tent time (or bathroom time, in a small glider proof bathroom) is great to try during the night or eve, when he is most active.

In the day time, carry him around in a bonding pouch. I like to take my gliders with me almost everywhere. If he isn't comfortable being toted around yet, you can keep him in his bonding pouch while you relax (watching TV/reading/surfing the net), any stationary activity really. He'll learn your scent this way too.

If you haven't tried scent bonding yet, it's really easy. Get some fleece, cut it into 4x4" squares, and tuck them into your dirty laundry pile. The fleece will hold your scent (and the scent of your family if you'd like). Then add a square of this scented fleece to his sleeping pouch. He'll smell you as he snoozes, and start to associate you with safety.

As always, a liberal handfeeding of his favorite fruit or vegetable, or yogurt on a spoon/your finger will be helpful in warming him up. Talk to him, give him treats, he'll come around!

And last for now, when you are wanting to take him out of his cage, either offer him a bonding pouch or pouch to climb into, instead of grabbing him. Gliders are prey animals and a grabby outstretched hand can trigger the instinct to panic, as it's not unlike bird talons or wild cat paws to him. Offer a pouch, and sweeten the deal with a fragrant treat to entice him in!

Ok I forgot one thing, but it's important enough to get its own post reply:

You should really consider getting him a sugar glider buddy, especially if you have a busy lifestyle. Single gliders can be more skittish on their own as they are colony animals and feel safer in numbers. Bonding with two is easier than bonding with one, as they learn from each other that you are safe and feel more secure with a friend. I bet getting him a glider buddy will really speed up him coming out of his shell. :)