What are the different Minhagim you or other people have with the drinking of the wine at havdala during the "9 Days"?
Do you drink it yourself, or do you use Chamar Medinah (a non-wine substitute)?
Which one is better halachicly? (You should probably define which Chamar Medinah you use, and if you give it to a child to drink, how old a child, and what gender.)
What if there is no child?
The Chazon Ish (quoted in Imrei Yosher, pg. 4) says that those who say Havdalah every week over wine or grape juice should do the same during the Nine Days as well.
In some places it is customary for a minor, if one is present, to drink the wine. The minor who serves the purpose should be a boy beyond the age of chinuch but who is not yet old enough to understand the concept of mourning the destruction of the Beis ha-Mikdash.[What this age is I do not know?] If such a child can not be found, any boy under bar mitzvah will do. (Mishnah Berurah 551:70).
While in other places an adult drinks the Havdalah wine. (Harav M. Feinstein in Moadei Yeshurun, pg. 154), the Aruch HaShulchan (O.C. 551:26) says people have the Minhag to drink beer (Chamar Medinah).
The Kaf Hachaim OC 551 sk 152, following the psak of Maran, notes the common custom among Sephardim is not to have any qualms about drinking wine at Havdalah during the nine days.
R'SimchasTorah's answer seems to cover many bases, but since the question seems to be asking specifically for as many people's respective customs as possible, I'll add my family's: we use chamar m'dina.
The Baal HaTanya writes in his Shulchan Aruch (295:4):
נוהגים שהש"ץ מבדיל בבית הכנסת על היין כדי להוציא מי שאין לו יין בביתו להבדיל עליו(וישתה מהכוס בעצמו אם נתכוין לצאת ידי חובתו בהבדלה זו או ישקה ממנו לאחר שנתכוין לצאת ידי חובתו אבל אם משקה ממנו לתינוקות אין שום אדם יכול לצאת ידי חובתו בהבדלה זו כיון שלא שתה מהכוס אדם שיוצא ידי חובתו בהבדלה זו):
Thus if a child drinks the havdalah wine then no one can fulfill hearing havdalah! It's not clear what his source is for this, however, and interestingly it directly contradicts what he wrote in 190:4:
אע"פ ששתיית כוס של ברכה מעכבת אין מעכב שישתה המברך בעצמו אלא די בשתיית אחרכו ואפילו מטעים ממנו לתינוק (כמלא לוגמיו של תינוק) יצא ידי חובה
But according to the first view, it would seem preferable not to give the wine to a child, despite the common custom.
This contradiction is pointed out in the Kitzos haShulchan 97, in the Badei HaShulchan #6.
Rav Shmuel Kaminetsky in Kovetz Halchos 9:18,19 holds one should make havdallah on wine and the person making it should drink the wine and they can use a regular size cup and finish all the contents.
In the footnotes(18) its brought that Rav Shlomo Zalman Aurabach would drink the wine himself instead of giving it to a katan. Rav Moshe also held that one should drink the wine instead of giving it to a katan.
Basically, there are 3 separate mehalchim 1. Just drink the wine or grape juice yourself (no difference b/t the two) (Mechaber) 2. Find a child and he should drink it; if you cant find one - then drink it yourself (Rema) 3. Beer - (Aruch Hashulchan)
Each of these views have a wide following among acharonim and contemporary poskim. Most Sefardim follow the Mechaber. Most Ashekenaim follow the Rema; although some Ashkenazic poskim do follow the mechaber on this, while others the Aruch Hashulchan.
Here is an excellent and extremely comprehensive article on this (including many contemporary poskim - worthwhile to go through the footnotes properly!): Havdalah During the Nine Days.
Most of the shi'tot were covered in other answers
While the Ramo recommended giving the wine to a child, the Mishna Brurah ((651:70)) pointed out that this cannot just be “any child.” The child utilized must have reached the age of training for brachos and will drink the proper amount, but not yet reached the age of training to mourn over Yerushalayim.
Rav Avigdor Nebenzhal pointed out in the name of Rav Shlomo Zalman Auerbach that it is generally difficult to find such a child who understands brachos but not the mourning for Yerushalayim. Accordingly, Rav Shlomo Zalman would drink the wine himself. It should also be added that given that Tisha B’Av falls in the middle of the summer, by the time Shabbos ends most such children will be asleep by that time as well.
Additionally, it might be suggested that even though for all purposes in Halacha (such as Kiddush, Havdala, Four Cups, etc) grape juice is considered wine, it still does not provide the joy of wine and might be a better choice of beverage on which to make havdala during the nine days.
Yerushalayim B’Moadeha, (vol. on The Three Weeks, #167)
