We got a swimming pool last week and now my 9yo is complaining of ear pain when he pushes on his ear. It's saturday so any home remedies? Or call doc?

Remedy swimmer's ear. Place a few drops of white vinegar in the ear. This will help lower the pH back to normal making the ear canal less hospitable for the bacteria that grow in a wet ear. To keep this from happening place a few drops of rubbing alcohol in each ear after swimming. Alcohol displaces water from the ear canal & then rapidly evaporates at body temperature effectively drying the ear.
Prob otitis externa. Mkst likely cause is inflammation/infection of the ear canal. Don't think you can get an antibiotic and/or cortisone ear drops over the counter (many other countries--yes, america no). So, give appropriate dose of acetaminophen, keep out of pool, warm compresses to ear and see doc (or call; the doc or associate on call may be able to help you via phone).
Swimmers ear. Also, if pain persists or is accompanied by swelling, fever, or drainage over next 24 hours do not delay in seeing an urgent care doctor to get started on antibiotic drops. Any history of ear surgery or chronic conditions would also escalate the need to see a specialist. Untreated external otitis can spread fairly quickly so be vigilant.
Swimmers ear drops. Over the counter swimmers ear drops might be effective. If increasing pain, fever or drainage then call your doctor.