You're right, it would need to be appealed. The defendant would not appeal, but the government could, and likely will if it views this as a significant burden to police practice. An important thing to note is that federal district court decisions are not binding on other federal district courts (the decisions are persuasive authority, but do not force another judge's hands). Any other judge could decide not to follow this rule. Only if the rule is announced by the 9th circuit would district courts in the 9th circuit have to follow the rule.
My main point is that while this is a promising decision, it is very far from the law of the land. And, as the original commenter pointed out, even if the 9th circuit upholds this ruling, the 9th circuit is only one circuit among many, and is often viewed as the most liberal circuit and not necessarily representative of the federal judiciary as a whole.