Earth was red flagged by the Andalites as of Visser. Before then the pool and blade ship defense was adequate, after that it was a bluff.
Once the Yeerks lost at Anati however, once Visser Three became Visser One Earth should have seen a major step up in security. The Andalites sent a major task force (I suspect the survivors of Anati who were in the best shape) to Earth right after they won Anati, I'm not clear on how large the force was but it would have been more than enough to wipe the floors with the Yeerk presence.
The Yeerks never stepped up security so the second naval battle for Earth was lost before it began.
Or was it?
Having given it some thought here's what I would have done if I had been in control of the defense of Earth.
First I send out a call for reinforcements, even if they couldn't possibly arrive in time, I'd want this to be intercepted by the Andalites, maybe they'd see it as a deterrent and not attack, far more likely they'd feel like my back was too the wall and their attack was all the more necessary right then.
Next I'd array my fleet, the Blade Ship, some bug fighters and any other attack ships I had I'd place near the moon where they could be detected but not immediately intercepted by the Andalite fleet. Planetside I'd forcefully procure as many human Space Shuttles as I could and build a few more of my own, I'd then fill them with as many explosives as I could, maybe human nukes but if I had anything better that I could spare then so be it. I'd have a few empty ones as well, you'll see why in a minute.
I'd crew them with involuntary human hosts, and one voluntary, the group commander. The empty vessels would have no explosives but be rigged to give off the impression that they were, indeed I wouldn't want the Andaliets to detect any sort of advanced shielding, I'd want them to know about the explosives, I'd have my fleet commander inform them that that was simply the human shuttle's fuel source, the Andalites know jack squat about human ships, they'd buy it.
Why would they buy it? Because they'd see those ships launching and trying to escape my bug fighters, which would be blasting the crap out of the empty ships, similarly they'd detect my offense fleet withdrawing from the battle, the Andalite meddlers would swoop in to the aid of the human ships which would radio themselves as being the human resistance trying to escape the planet, claim that the Animorphs and Aximili had given them prior knowledge of the Andalite's fleet movements. They'd claim to be full of women and children, I might use real women and children to complete the illusion, and if the sensors could pick up actual yeerks I'd just have the yeerks themselves morph humans so that no Yeerk lifesigns were detected on the ships.
So with my fleet of explosive space shuttles heading for the Andalite fleet and my pool ship trying to back away I'd have the fighters attacking the shuttles withdraw to defend the pool ship, make it look like I was trying to get away, meanwhile the phoney human resistance fleet gets closer and closer and when they're just close enough to the Andalite fleet . . . BOOM, baby! Baring the Andalites suddenly realizing what's happening (And even then because I'd sort of want to use explosives that would take the Andalite fleet without having to be right in there among them) They self destruct, the Andalite Dome Ships get thrashed, the Blade Ship, bulk of the bug fighters and whatever else I had pretending to flee sweep in to finish the Dome Ships, destroying but more importantly
disabling whatever they can, the Andalite fighters, which would have left the dome ships defenseless to chase the pool ship, or else escorted the human ships in and been destroyed in the blast or vaped by my own fighters and blade ship, would probably try to go to Z-Space, or make a break for the planet. If they try to land on the planet I have a warm welcoming party waiting for them with the objective of capturing the fighters intact and stunning any Andalite warriors for infestation, I'll assume however that the Andalites either die or escape to join the Yeerk resistance, capturing even one pilot would be a major boon but I wont count on it.
I win even if they go to Z-Space, which I doubt they would given that nobody from the Galaxy Tree made the attempt despite the fact that their Dome Ship was destroyed long before the battle ended I assume the nearest relief is further away than a Fighter can manage.
When the space dust settles (which I guess it never technically would) I'd have teams go out to salvage every Dome Ship and Andalite fighter I could, what fighters I couldn't replace on the Dome ships I'd fill in for with Bug Fighters, crew them with Hork-Bajir and morph-capable humans, then using Visser One's caputred body (or preferably a different Andalite if I'd gotten one) I'd send a message to the Andalites that the invasion of Earth had failed terribly and that the survivors were inbound for repairs and refit.
Then it's a simple matter of deciding where my fleet of captured and pieced together Dome Ships would go. To the Yeerk Homeworld to free it, or the Andalite Homeworld to
burn it.
And Jake and his group? Believe me, if I were in control of the pool ship they'd have been properly dealt with the minute they set foot on
my boat, they wouldn't have made it as far as flushing that pool of Yeerks because I'd have beat them to it while they were still in the room and just blamed it on them (hey, I'm a Yeerk, my survival comes first) and the Yeerk in control of Tom had darn well better know better than to try to steal the Blade Ship and attack the Pool Ship on my watch because I wouldn't have waited until after Rachel died to shoot that traitor out of space, I'd do it the minute they came in on an attack vector, and the swarm of bug fighters tailing him would be crewed by Yeerk loyal to Visser One (or me, I figure if I've got nominal command I'm probably at least a sub-visser . . . please don't let me be Taylor
)
And if you read all that, well what can I say? You
are a trooper.