M.,
First of all- you are obviously a GREAT, CARING Mama. That's why you want to make sure your son is safe, and you're doing the right things.
My daughter used to cry most the night- (she would never sleep.) There were times I would go into the bathroom, turn the shower on, and the fan and cry. I was so frustrated- I thought I was going to pull my hair out.
He's 9 months old- that means he's a little older and is able to go longer periods of time without you. I would let him have 'work it out' time of about 15-20 minutes after you comfort and soothe him. They have to learn to cry and comfort themselves, too. We're very used to coming to their every tear, or noise that they get used to that too- that's what makes us awesome moms. But as they get older, they need to learn to depend on themselves a bit more. I wouldn't go over 15-20 minutes without going into check on him, (some kids have been known to get SO upset they hold their breath or throw a giant tantrum.) He's still little enough that he doesn't quite understand. All he understands is mom used to come when he cried- right away, and now it takes her longer.
I started putting my daughter to bed between months 8-12 with a cd player of lullabys. It seemed to help lure her back to dreamland and I put it on repeat to keep her out all night. (After she was a year old- she wanted no music.) It's been a struggle.
I think it takes courage to come out and say what so many of us feel. We're- EXAUSTED. But by saying that you're tired and reaching out- I think that deserves major kudos.
You mentioned that your husband is a cop- and undeniably I'm sure he has a very stressful job and needs his sleep. However, he helped create this screaming bundle of cuteness, so he shold also be stepping in to give you an occasional break. Sometimes men think that when they work outside of the home, it's all up to the wife to raise and get up at night with the kids. And although I understand the stresses of outside employment, it's very hard staying home, too. Some husbands are better than others. :)
-Hang in there. Sometimes it's alright to go upstairs/downstairs- (away) from your son. Eat some ice cream- turn on music louder- watch part of a tv show. EVERYONE deserves a break. You couldn't be the best mommy without making sure you're being taken care of too.
-Good luck!