Wally was a one-time character in the series and one of Tommy and Gus's friends. Tommy and Gus had a sleep-over at Wally's house in the episode The Sleepover. They and some other friends destroyed Wally's house and were disrespectful to Wallie's Dad. Later they mention that the year before the police had to come to stop the sleepover. The seem to get along with Wally and he seems like a good friend. But this is the only episode where Wally shows up or is mentioned. It is possible that he lives outside Bay Area and therefore goes to another school.