Hi, I am Dr. Peter and would like to help.
1- When you look inside his ear with the light, did you see any redness, moisture, or foul odor?
The ear canal of a cat makes a 90 degree turn toward the head. With a plain light you can see the outer part of the external canal. But, to look deeper and turning the 90 degrees will need to have a hands on exam by your vet to look in there with an otoscope. There could be something deeper in the canal that you are not seeing. Things that can be found are ticks, polyps, etc. These are usually not very serious but important to rule them out. Consider having your vet take a look before you go into vacation.
If you have additional questions I will be glad to answer them.