Assuming your glass break and motion detectors require about 30 mA each, you'll need a total of 0.7A of current to power them. The M1 might just be able to power all that, depending on what other stuff you have connected, such as keypads, zone expanders, smoke detectors, etc. But my guess is you are going to need an aux power supply.
You could go with one of the Elk power supplies, like the P112, P212S, or P412S (the P124 you mentioned is a 24V power supply). I'd probably skip the P112, as that has only 1A output, and would be barely adequate to power the motions and glass breaks.
With these, you can use an Elk PD9 distribution board to make the wiring a little easier rather than wire nutting all the power wires together in one big bundle. Some folks like to use terminal strips, and that's ok, too. The distribution boards give you individual fuses on each output, so if you get a short somewhere, it doesn't take out all the devices together. Still, with the number of devices you're planning on, you'll have 2 or 3 on each output.
Another option would be an Altronix power supply, like the
AL400ULPD8. The PD8 includes an 8 output distribution board. There is also a PD4 model, with just 4 outputs.
I'd go with a separate power supply for the cameras. I'm guessing you'll need about 5 Amps capacity for 8 cameras, depending on what model of camera you get and whether they have IR LEDs or not. Do you plan on using PoE to power them, or will you hardwire 12V directly to each camera? An Altronix
AL600ULPD8 will probably give you adequate power, plus battery backup if you want that. If you don't care about battery backup, something like the
ALTV1224DC2 might be a better choice.
If you are going to use PoE, you might want a PoE power supply like an Altronix
Netway8.
You can often find a variety of Altronix power supplies in new or used condition on eBay at a substantial discount.