"The wines are good."
Translation:Os vinhos são bons.
It's simply a case of gender and number agreement. If the noun is masculine-singular, feminine-singular, masculine-plural or feminine-plural use "bom", "boa", "bons" or "boas" respectively. So here "os vinhos" is masculine-plural and the appropriate adjective is "bons". (There is no such word as "bon".)
Both "sou" and "são" are present tense conjugations of the verb "ser" (to be) and have nothing to do with gender.
You say "Eu sou bom" (I am good), "Ele é bom" (he is good), "Nós somos bons" (we are good) and "Eles são bons" (they are good). The thing that changes with gender is the adjective and for females the same sentences become "Eu sou boa", "Ela é boa", "Nós somos boas" and "Elas são boas". In this case "Os vinhos" is, grammatically speaking, masculine-plural so the correct form is "Os vinhos são bons" (the wines are good).
Portuguese has two "to be" verbs, "ser" and "estar" and two versions of "are", "são" and "estão" respectively. When you say "The boys are good", for example, you can translate that as "Os meninos são bons" or "Os meninos estão bons". In the first version you mean the boys are inherently good and in the second that they are good right now, today or over a similarly short time scale. Although you could argue the case for "estão" in this sentence, "são" makes the most sense I believe.
Well done! Only a observation: may be that the phrase "Os meninos estão bons" makes more sense if we use a period here where we are speaking about people "Os meninos estão bons hoje" / "Os meninos estão bons este ano", etc. Congrats for your Portuguese.
Portuguese: Dominate verbs and pronouns and everything will be fine... hehehe :)