Transmission - Pressure Switch

Maybe the magnet did it's job, why else would it be magnetic? How many miles in 9 years to collect that stuff? It may be normal.
Replacing the switch is not a common repair.
Considering the age, etc. I would do a fluid exchange (gentle flush) to be safe, but not at a shop hoping to replace the tranny.

I've needed a pressure switch changed while traveling (can't remember if it was #2 or #3). A Honda dealership repair shop installed a new switch in less than three hours including waiting for a slot to open up and the stack of paperwork. I bet the mechanic was under the truck less than 30 minutes.

We need more information: why did they replace a switch (did it throw a code?), are you the original owner, have you regularly changed the trans fluid, is this a Honda shop, independent repair shop, or a transmission shop etc?

"Fuzz" on the plug is not unusual.... especially if the fluid change interval was not adhered to (if it's been a long time since last change).