You can't use sample images to judge potential quality. Only test shots, like those at imaging-resource.com, can show the real differences between cameras. Using that site's image comparometer, you can clearly see the advantage the D90 and XSi have over the H9, especially as ISO rises. Also to consider is that a DSLR is a system, with lenses being a huge factor in image quality. Good quality lenses can be very expensive; lenses will cost more than the body. So if you're after better image quality, be prepared to spend a lot if you are trying to cover the same focal range as your H9, most especially if you toss in the low light requirement.
I'm looking to upgrade my Sony DSC-H9 to a DSLR to get sharper photos (especially at high ISO) with better depth of field & better background color saturation (i.e. for landscapes). I'm looking at the NikonD90 and Canon xsi. The reviews for both have been great for starter DSLRs, but when I look at some of the images posted online from each of these, some are equivalent to what I can capture with my Sony. I realize some of this has to do with user experience, but I want to know if I upgrade to one of the above DSLRs, will I see a noticeable improvement in photo quality. If not, I may not make the upgrade or will look a bit higher on the DSLR scale.
To provide a little background, I use my Sony for everything from landscape (day/night), portrait, wedding, pet and some action shots. I anticipate needing more action shot & portraits capabilities (especially low light) as we start a family in the coming year. I want to capture as good quality photos as I can as our kids grown up. Thoughts? Suggestions?