Contrary to the other commenters rose colored glasses, as someone who ran OS9 at the time, it was indeed very unstable.
The entire MacOS classic line of OS’s were horrible for stability. Any small bug in any program could knock out the entire OS, and they did multiple times a day. Don’t get me wrong, the love put into the OS was palpable. That’s why you used it. It just crashed all day every day.
I didn’t have this experience, but perhaps because I mainly played games at the time. Maybe the type of games I played just crashed the system less than -say- productivity software.
I want to counter the idea that OS 9 was either stable or not stable. I made money in grad school fixing people's Mac OS 9 setups, and I had many satisfied customers. Basically, one bad Apple spoils the barrel. If you add "crazy media network extension from hell" alongside all your dozens of working apps, then yes, the whole OS becomes unstable. Similarly with low-quality Photoshop plugins, OS startup services, odd hardware drivers or even corrupt font files.. yes, the whole OS can crash "daily".
On the other hand, like a great day at a public theater act, when it goes well, it really does go well. I have OS disks and applications saved to this day, in their own filing system in a drawer, that run great, look great, and are a joy to use. And so you know, months of daily, extensive use, with no crashes.
I didn't start using a mac until iPhone development started, so the earliest version was 10.5 for me, but in that and later versions, the entire system could be crashed by corrupted fonts, not even system fonts.
OS9 was very stable, but some apps weren't e.g. photoshop would crash a lot, and as there was no protected memory space for processes every app crash balked the entire system. Happy days.
Oh it wasn't robust by todays standards (or any standards really), but it would be wrong to infer from that that the quality of OS9 was inferior to OS8, OS7, rotting, etc.
I say as a Mac user, while not inferior to other MacOS’s, it was however inferior to the stability of the counterpart versions of Windows, more-or-less since inception. The stability gap got wider and wider as the years went on and Windows 2k made OS9 look like a joke. OS X closed that gap and then quickly surpassed it.
I still think the distinction is (a bit) valid. You could run a stressed mail server on os9 for a year with no downtime/ no maintenance. The chances that the afterthought mac port of the windows software that you need to run would be flakey? - pretty high. These apps crashed just as much on osx, at least until macs become popular enough to not be able to get away with it. The process isolation made it more bearable, but you'd still lose your work. The benefit of osx wasn't spontaneous reliability (although, some things - font handling, printing - ok, it kinda was), it was that you could now run high quality open source alternatives (it's weird to remember just how difficult that was on OS9).
Heh. Small, but not stable. I suffered it at home. Sound/chipset driver install = BSOD. "High" load on IE with several (less than 10) Windows open = BSOD.
The entire MacOS classic line of OS’s were horrible for stability. Any small bug in any program could knock out the entire OS, and they did multiple times a day. Don’t get me wrong, the love put into the OS was palpable. That’s why you used it. It just crashed all day every day.