So I’m not sure if you’re aware of how common law works: but the constitution establishes the principle of the Supreme Court, which is the ultimate court in making determinations of law. It’s not just the constitution that matters, it’s also precedent from common law.
The constitution basically provides the equivalent of unappealable president - eg; if the constitution says no, then the answer is no.
If the constitution doesn’t say anything in a contested matter; then the courts and Supreme Court has authority to make an ultimate ruling on it; this forms the principle of precedent that must then be followed by other courts.
For example; in the constitution, naturalization is given exclusively to the federal government, and previous precedents it’s established that and Federal government has jurisdiction on immigration.
Which kinda makes sense, you don’t want California to, say, vote to grant legal status to illegal immigrants; who then may cross into other states: the whole premise of a federal system is to be able to mediate issues where one states rules impacts an other state (part of the Commerce clause).
The issue is not that 9 judges have this power; it’s that in a system of laws and torts, you will always require some ultimate arbiter of what the law means, how it applies, and to rule on whether individuals have crossed the line.
The only question is who that is. Is it for the people to decide? It already is; you have the ability to elect people in Congress and to the president to chose the Supreme Court appointees: to ammend the constitution - ultimately overriding what the judges say.
Saying that, Prop 187 never made it to the Supreme Court for them to make that decision - it went through the court system, and the challenge was pulled by Gray Davis in 1999.
The suggestion that the court should only rule on the explicit content of the constitution, very much cuts both ways:
For example Granting legal status to illegal immigrants - against precedent, but not against the constitution.
All blue states could require militias to be registered and regulated; and weapons ownership could be limited to those who have signed up as part of a militia, with the weapons to be stored in secure facilities run by that militia, and not carried personally. That meets the text of the 2nd amendment, but not the established precedent.
There’s many more I could list that fly in the face of what we have established in precedent but not the constitution.
As mentioned, the constitution itself you have the checks and balances that give control over the courts; democratically elected federal officials control nomination and appointment, and removal of federal and Supreme Court judges.
The original statement in your title, though, has some merit.
The constitution itself, has no specific worth other than what you give it. If people think the constitution is worthless, it becomes so.
If for example, a President abuses their power, overrides congress on spending power; refuses to submit to confessional oversight - the constitution expects that the house will impeach and, of the accusations are true, the senate will convict - but if the senate don’t care, and acquit regardless of the evidence because the person is in their party - the constitution is meaningless.
Likewise, if a party, say, intentionally loads the federal bench with unqualified partisan hacks for the primary purpose of being able to jam through their laws, and oppose their opponents; then there’s not much you can do; if that same party then uses that court to say, override election results, enact laws that disenfranchise one side; and allow for substantial partisan gerrymandering or restriction of the press under the guise of “disinformation” ; then you've not only shown the constitution is worthless; but you’ve also lost your democracy along with it.
The constitution is only meaningful, if doing the right thing, acting in good faith, adhering to the rule of law is more important than winning; and that both sides recognize that in the other.
The issue here is not the judges; or the power they have: it’s that when you see decisions you disagree with and assume it’s abuse; circumvent the constitution to stop your guys losing power, and support jamming of partisans onto the courts because they’ll agree with you; and you support whatever actions lead to you getting the policies you want - that’s when the contrition becomes worthless.