It's a USB 2.0 port, which by definition is 5V and 500mA.
In reality, often the real world devices within embedded systems on a chip fail to even provide that rated power.
I've found by experience that most of these devices fail to meet their declared power rating and even their data rates fall well short of the expected specification.
The only thing I can think of, and I'm not sure if the USB port recognizes them, is to provide a hub powered from the accessory outlet on the bike. I can only assume it might, as there are accessories out there that supply multiple USB ports, but I suppose they may only be one port for data and the rest just for power. I have a small hub that I'm going to try when the temperature in my garage drops below 100°F again.
I'll plug the power for the hub into a 110V outlet via a wall wart, plug the dash USB into the host side of the hub, and then test to see if each of the output ports on the hub will connect to CarPlay before I bother to wire it into the bike's 12v accessory power.
If you have a USB hub available that test will prove whether it works on not. You can bring power into the glove box where you can fit a small multi port hub. A powered hub should give you more than enough power, you just have to find out whether the USB port on the Spyder supports hubs or not.
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On second thoughts it might not work. The phone might negotiate the power with the host, the Spyder, not the hub. You'll probably have to try it and see.
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If this doesn't work try the following on Amazon, it's like $12. It takes its power from a USB C port. You'll need a USB A male to USB C male data adapter to attach it to the Spyder USB A port.
USB 2.0 Type C Signal Separator, Aluminum Alloy USB C Power Splitter Module
USB 3.0/3.1 Male to USB-C Male Adapter (2 Pack), OTG 3.0/3.1 USB A to Type-C Adapter, Fast Data Transfer up to Gen2 10Gbps, USB C Connector Connection or Data Cable Extension
Waterproof DC 12V/24V to 5V 3A Buck Converter, USB-C Output | Stable 5V/3A Output, Waterproof Sealed Enclosure, Built-in Multi-Protection
Green Jiss® USB C Extension Cable 5ft, 20Gbps/4K@60Hz Video, Heavy Duty USB3.2 Gen2 Extender Male to Female Full Function Ultra-High Speed Transfer USB Type C Extender 240W Fast Charging Cable
In order to get ignition switched 12V power from the Spyder you will need the following from SlingMods:
Plug N' Play 12V Aftermarket Accessory Quick-Connect Power Harness for the Can-Am Spyder RT (2020+)
So what does all this stuff mean:
1. The SlingMods harness will give you 12V power.
2. The Buck Converter will convert 12V power to a USB 5V supply. Its bare end wires will connect with the push down connectors on the SlingMods harness.
3. The USB C cable will take power from the USB output of the Buck 12V to 5V Converter up to the glove box over a quality USB C cable.
4. The signal separator will take the Spyder USB A cable, via the USB A to USB C convertor to the host side of the signal separator.
5. The USB C cable you ran from the power converter to the glove box will plug into the USB power input on the other side of the signal separator.
6. From the USB C output of the signal separator you run a quality USB C data cable to the phone, USB C male to USB C male assuming your phone is USB C. Id didn't specify this as I have no idea how long you want it. Use a high quality USB C data cable.
What you are doing here with the signal separator is that the data at the low wattage comes from the Spyder to the separator. The USB power is then stripped and the data is forwarded to the phone at the power rating supplied by the signal separator to the phone. So, the phone negotiates power level from the power separator, not the Spyder. The other parts are just a way to get 12V power from the Spyder turned into 5V USB C power to power up the signal separator. I suggest using electrical tape down at the SlingMods harness end of things. The power convertor is already waterproof.
I hope one or the other systems works for you.