can I create and alert to alert on temperature on Cisco devices ?
What is collecting the Temperature metrics on Cisco devices ?
Is there a Poller existing or do I have to create a poller ?
Here's some native functionality: Hardware health OIDS - SolarWinds Worldwide, LLC. Help and Support
How to create an alert from this: Create a hardware health alert for power supply issues - SolarWinds Worldwide, LLC. Help and Support
I realize your question is about temperature, but it's trivial to change this step:
Have a look in settings under "Manage Hardware Sensors" here you will find all the sensors and you can set thresholds for them.