According to Official Guinness Records,
The most bouncy balls scooped in 30 seconds was 29 and was achieved by Emiko Hanada (Japan) during the Park Challenge / GWR Live! at Tokyo Midtown, in Minato, Tokyo, Japan on 1 May 2012.
This was part of the 2012 Park Challenge event in Tokyo Midtown.
For a complete list of 2012 records, please visit 2012 Guinness Records in Japan.