Kan vi bli överens om att gå hem nu?

Because this is a yes/no question. In Swedish, yes/no questions usually put the finite verb first.

• Statement: Vi kan bli överens om att gå hem nu.
• Question: Kan vi bli överens om att gå hem nu?

So this is normal Swedish question word order.

It can feel a bit broader than simple ability. In this sentence, kan vi ...? often works like a polite proposal or request for agreement, similar to:

• Can we agree to go home now?
• Could we agree to go home now?

So it is not only about physical ability. It can also mean is it acceptable / are we willing.

Överens means in agreement / agreed.
Bli överens literally means become in agreement, so the natural English idea is reach agreement or agree.

So bli överens om ... is a common expression meaning agree on/about ...

Because bli shows a change of state: you were not necessarily in agreement before, but now you reach agreement.

Compare:

• Vi är överens. = We are in agreement.
• Vi blir överens. = We come to an agreement.

In your sentence, the speaker is asking whether the group can reach agreement.

This is the same change-vs-state distinction:

• vara överens = to be agreed, to already be in agreement
• bli överens = to become agreed, to come to an agreement

So:

• Vi är överens om att gå hem nu. = We already agree about going home now.
• Kan vi bli överens om att gå hem nu? = Can we come to an agreement about going home now?

Because överens om is the normal pattern: you are agreed about something.

When what follows is an action, Swedish often uses:

• överens om att + infinitive

So:

• överens om att gå hem
• literally: agreed about to go home
• natural meaning: agreed to go home

This is just the standard structure after överens om.

Because after att, Swedish normally uses the infinitive form of the verb.

• infinitive: gå = to go
• present tense: går = go / is going

So att gå hem means to go home, which is exactly the form needed here.

Because gå hem is the normal idiomatic way to say go home in Swedish.

Just like in English, home often works without an article in this kind of expression.

• gå hem = go home
• komma hem = come home
• vara hemma = be at home

Hem here means movement toward home, while hemma means being at home.

Nu means now, and it adds the idea of at this point / already / now rather than later.

Its position here is very natural:

• Kan vi bli överens om att gå hem nu?

That said, Swedish word order is somewhat flexible, and moving nu can slightly shift the emphasis. For example:

• Kan vi nu bli överens om att gå hem?

This puts more focus on now as a kind of finally / at this point. The original sentence is the most neutral.

Yes. Komma överens is very common and often sounds especially natural in everyday Swedish.

• Kan vi komma överens om att gå hem nu?

This also means Can we agree to go home now?

The difference is small here. Both are correct.
In many contexts, learners will hear komma överens very often.

It is grammatical and natural, but it sounds a bit more like trying to reach agreement than a simple suggestion.

If you just want to suggest leaving, simpler everyday options are often:

• Ska vi gå hem nu? = Shall we go home now?
• Kan vi gå hem nu? = Can we go home now?
• Kan vi inte gå hem nu? = Can't we go home now?

Your sentence is especially suitable if there has been discussion, hesitation, or disagreement, and the speaker wants everyone to settle on the decision.