Is that with an AT&T 640? Often the hotspot feature will work on a factory unlocked phone even if it is not on the plan, or the carrier does not support it. I used to use the hotspot all the time with my factory unlocked Nexus 5 on Net10. Net10 does not support tethering at all. It is not even optional.
Don't believe ANY 640 will support HotSpot on Cricket. I'm not sure how they control that feature, but I do know their motive for doing so. They sell a pretty robust 10 Gig data plan for about $60 ($55 with autopay) per month. And I suspect they have
data that reveals that a non-tethering customer will not use nearly the average of that allotment as a Hot-Spot\Tethered customer will. So they want that extra $10 per month for those customers.
If Cricket actually sold larger (extreme) data plans for us rural folks, that have nothing but LTE vs Satellite internet, I would likely have gone with them, even with their silly device limitation. My brother uses a throwdown cheap Cricket Droid for a hotspot at his house. Leaves it in the window sill and never touches it. Works really well for his country hick ISP.
But I don't even have SAT or Cable TV. So it is OTA and Netflix at my shack. That HUGE AT&T data plan (on all devices) opened up a brave new world for my household.