Definitely!
Make sure your bike is in good working order: tires inflated, chain lubed, gears adjusted, hubs adjusted and lubed (depending on construction, "cassette bearing" types should be maintenance free), wheels aligned, brakes adjusted, lights working. All these are minor works that can easily be done by yourself - there is a lot of info on the web.
Then, take some effort to adjust the saddle to the correct height. I see so many people riding with their saddles too low - which will only hurt their knees and even require greater effort!
Wear shoes whose sole has approximately th esame thickness. No, no high heels, no plateau. Just shoes. Sit on the bike - preferrable next to a wall. Put both feet on the pedals (you will keep your balance by leaning onto the wall with one of your arms). Now put your heel on the pedal. Adjust saddle height so that your leg is straight. Check with the other side. If this works, in the next step assume yor riding position: put the ball of your foot on the pedal, where they will be when cycling. Now your legs should be slightly bend even when the pedal is on it's lowest point. Check by pedaling backwards*: When the pedal is down, your legs should be almost, but not entirely stretched, rather slightly bent. You should be able to pedal this way without your hips moving. If your hips are moving, lower the saddle slightly. Check again with the heels on the pedal -> legs should still be straight. Now balls of the feet on the pedal, check again if your hips don't move... This can be a millimetres' game and take a while.
Congratulations, you're set. Now ride your bike! And no excuses about it being "only a cruiser"! In the first half of the 20th century, cyclists were tackling the tour de france and the giro d'italia on primitive single speed bikes. If my Grandpa could conquer the Alps on a single speed bike, that small hill should not stop you. ;-)
I would rather not start commuting by bike immediately as you stated to be overweight and out of shape. 9 Miles is roughly 14.5km, which for an experienced cyclist is a piece of cake. However, after a long break it can be quite hard. In my youth, I regularlky drove 120km (75 miles) in a single training unit - when I resumed cycling after several years break, a short spin of 25km left me destroyed for the rest of the week, even though I had always done at least some kind of physical exercise.
So I suggest you take the bike out for a spin around the neighbourhood after work, you do some tours on the weekend to build up some endurance and confidence. After some weeks, do a test run on the weekend - drive to your workplace and back. Having done that, you know how long it takes, and that you shall definitely survive the exercise.
And remember: cycling does not get easier with practice. Never. But you will get faster. A lot. :-)
Cycling to work and back and doing your shopping by bike should solve the weight- and out-of-shape issue in no time.
On the financial side, I'd suggest to rigourously cut eating out. Even if it's your "dating". You can have the romantic dinner - at home. Guess what I do every weekend? An over-the-top 3-course menu for two people can be prepared for 25€, including a really good wine. In a restaurant you would spend 80-120€ for that quality.
*Obviously, pedaling backwards does not work on a bike with coaster/backpedaling brakes.
