K-9 / rolling in the dough

Reader's Digest 2月号の記事 "HOW THEY CAUGHT THEIR STALKER" から引用します。

BELMONT, NEW HAMPSHIRE (population 7,200) is an old mill town surrounded by lakes and forests. A hardware store and a hair salon are about all Main Street has to offer. At the local police department, a donation box is stuffed with change and dollar bills to support Vito, the department's K-9. "We don't have a lot of people who are rolling in the dough," says Raechel Moulton.

まず "rolling in the dough" ですが、"dough" にお金の意味があることから、金回りの良い、つまり裕福な人を連想できます。辞書で確かめるとWiktionaryに "roll in dough" はSynonym of roll in wealth とあり、"To be very rich" の意味だと分かります。又、Merriam-Websterには "rolling in (something)" の項にhaving a large amount of (something)："What did you mean when you said they are rolling in (the) dough?" "They're rich". と説明がありました。
蛇足ですが、10/21/2020に "pulling in the dough" を取り上げていました。

次に略語のような "K-9" を調べます。

・Wiktionary: A trained police dog.
・Wikipedia:
a) the nickname of police dogs and the police dog unit itself
b) Canine or Canis, a genus including dogs, wolves, coyotes, and jackals
なるほど、"canine" から転じたのですね。