Are Italian and caro kann good openings for beginners?

Italian is good for beginners.

Not so much Caro Kann. Just focus on basic open positions that come after e5. Against d4, just play d5, aim for a Slav setup.

The Caro Kann is my bread and butter when playing the black pieces. But I don't think it's the easiest opening to learn as a beginner - there's many different lines that you need to know about and memorize. And I feel that as a beginner, it's much more important for you to focus on building good chess habits - things like developing your minor pieces, castling you king to safety early, getting an escape hatch so you don't get back rank mated, connecting the rooks and moving them towards the center files. Blunder checking before each move and improving your board vision. All of these are much more important than trying to learn the Caro.

In a lot of lines, the Caro falls behind white in being able to castle, and that alone, as a beginner, can get you into a lot of trouble. So while it's a great opening, I wouldn't start your chess journey with it.

A question along this line of 2 openings.

As an assumption that 80% to 90% of white openings are either 1.d4 or 1.e4, Is it better to learn 2 openings in depth, one for playing black and one for playing white? Or should one learn multiple openings just superficially?

I play both of these openings, and I would say that they are some of the safest, most flexible openings in chess. See if they suit your playing style.

The Caro might not be the absolute best for beginners. Never play the KID unless you are 1000-1500+

Seeing that you are 1010, I still wouldn’t recommend the KID.

I recommend Scotch over Italian. Italian is too heavy theory alongside Ruy Lopez and still very popular among GMs. I also recommend French over Caro-Kann because you will only face 4 serious lines (Advance, Exchange, Tarrasch, and the Normal 3. Nc3) that's it. White has too many replies against the Caro-Kann.

I play both Italian and Caro, both are great if your opponent allows it. For white if you go e4, black does not have to play an Italian. They can play a Sicilian with c5, a Scandinavian with d5, a Caro of their own with c6, a French with e6 a pirc with d6, a modern with g6 and many more. And with black your opponent can go for d4 (queen's gambit / London) or c4 (English) instead of e4 which can lead into a Caro.

So for a beginner what is important is not learning a specific opening (you won't always get games you practice lines for), but instead learning about good development principles (especially king safety), focusing on good pawn play and working around specific pawn structures (that are common among many openings), blunder checking and spotting tactics, and learning basic endgames (mating nets, opposition, passed pawns etc.). These will help you in every game, not just a specific opening that you are preparing.

The only opening theory you need to know as a beginner is avoiding opening traps, it is worth memorizing those.

Plain old King's Pawn is more solid.

Yes, both the Italian Game and the Caro-Kann Defense are excellent openings for beginners.

Openings won't be helpful for that.

Nor playing 5 min blitz exclusively will be of any help.