@Rene *****
it's and unlimited number of entries.
We often refer to nearly 9 months stay because that's a good way to use the visa, as opposed to "just" entering multiple times during some extended holiday through the region. The latter can also be done on exemptions (if you qualify) and perhaps an occasional SETV. Staying 9 months on the other hand is not so easy with these.
Mind you that 9 months isn't the maximum stay - the theoretical maximum is 269 days but that requires either a day abroad on one of the bounces or an extra bounce. It also requires teleporting to Thailand on the day the embassy grants the visa, which indeed sounds a little optimistic. If you book flights upfront you need to buffer enough time for a potential initial refusal (I personally think you shouldn't book final flights yet because you are asking permission to enter the country and haven't been given it yet. So work with some workaround and book your actual flights later). Lastly, a minor: 270 days is also at least 3 days short of 9 months, and the way Thais count these days, you lose yet another unless you land right after midnight and leave before it.
All in all, getting 8 months 3 weeks from the visa would be the extreme. Getting 8 months 2 weeks would be very well done.