Reading USB Relay Specifications

It's a 12V relay (it clearly says "12V DC").

The picture on the left also says 5A @ 250V AC. That's something, but relays are quite complex and have many important parameters.
In that sense the other one is easier. It says "Takamisawa" and that's a Fujitsu brand. For the rest just make some guesses. Google for "Takamisawa 12MB". Bingo! We get hits which also say "VS", and that's also on the relay, so the type is probably "VS 12 MB". On the Fujitsu website look for power relays. We're on the right track, because there is indeed a "VS" series.

Now we have the datasheet we can find just anything we need to know. Like your question about 9V. They're 12V relays, will 9V be enough in the first place? Coil ratings are on page 3. This is a standard device (high sensitive types are "SMB" instead of "MB"). The table says that the "Must operate voltage" is 8.4V, so the 9V is sufficient, but doesn't give you much headroom. If you switch the relay with a transistor you'll have a few hundred millivolts voltage drop over the transistor and if the 9V has some tolerance too the relay may not operate! A MOSFET as switching element may be a better choice than a BJT. A low \$R_{DS(ON)}\$ type like the NTR4170N (just a random type) will have a voltage drop of just a few mV.
Coil resistance is 200\$\Omega\$, so current will be \$I = \frac{V}{R} = \frac{9V}{200\Omega} = 45mA\$. Power is then only 405mW, while the rated power is 720mW, so it's clear that you're near the limits.

Bottom line: use anything printed on the relay + your imagination, and you'll often find any information you need.

Q & A (from comments)

Q: What is the difference between coil's Rated power and Operate power?
A: Operate Power is the power at the minimum required voltage ("Must Operate"): \$\frac{(8.4V)^2}{200Ω}\$=350mW. Rated Power is the power at the nominal voltage: \$\frac{(12V)^2}{200Ω}\$=720mW. If you can't work at the rated voltage, at least try to stay as far as possible above Must Operate Voltage; this is the absolute minimum for guaranteed operation.

I've had the same problem in the past. It looks like there is no public spec available. Instead Motorola (SPI's originator) had timing diagrams in datasheets for controllers supporting SPI. For instance the 68HC11 datasheet has SPI timing information in section 10.17, on page 171. General SPI description on page 119 ff.

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"The SPI bus is broadly accepted because it has little or no patent issues. This is partly because Motorola, its creator, provides no specification or central support. Those applying SPI can create hardware and software solutions without patent issues, but also without support or definition of supporting protocols." (source)