Hi @nasahtahir ,
Post an image of the household power socket that the plug has to fit in to? Here's how to do this on iFixit [guide|21499].
The power cable for a 65W charger may be rated less than what a cable used for a 90W charger would be so yes it would heat up it it were used to connect a 90W charger instead.
Check what the input current specifications (if any) are on the information label of both the chargers if you have them that is. Also check closely on the cable itself. Sometimes the specifications for the cable are printed on it somewhere. If the values are the same (they may be to save money by using only the one type of cable) then it is OK to use it. If not then obviously don’t.