Dry food is the only viable solution. Wet food will spoil in less than a day in your heat.

The only other solution is to find someone to come by and feed the kitten once a day.

Of course water is the most important and you seem to have that solved. Are you also providing shade?

Here, for water, I use automatic sprinkler timers that come on twice a day and drip water into several bowls around my property. These timers just attach to the hose bib and run on a battery. They are sold in hardware stores, plant nurseries, and, of course, online.

I also have a battery powered dry food feeder that opens twice a day according to the times you set.