Ahh, that is the big question that plagues many a tree-putter-upper-er across the globe. When do you put up that darn old tree?
Well, I guess it depends on where you come from, what your family does and what's considered normal for you, and what you feel like doing.
For myself, I think that the 1st December is a great date for putting decorations up. Just because that's what I've always done, so it's normal. Any earlier would just be weird!! You'd start turning into the shopping centres who have them out in October!
For other cultures, for example England, many trees would go up around 12 days before Christmas (hence, the 12 days of Christmas).
Some people go the day before Christmas, a month before Christmas, or whenever they get the time to do it.
In short, there is no simple or right answer for your question :)
But if you feel the need to have your tree up in September, to start with the excitement, then go for it!
A star or angel
yes
To put the present under it
It really isn't too early too put up the Xmas tree for it all depends on if you have the Christmas spirit. In 2 weeks is the first day of advent which is when some people put their Christmas tree up so it is perfectly ok to do so.
You don't. Christmas trees have nothing to do with Hanukkah. If you put Hanukkah-style ornaments on a Christmas tree, it will most likely offend the people you are trying to honor (even if they don't tell you that).
The two most popular Christmas tree toppers are a star and an angel. The angel tree topper, however, is only favored by about 9% of people who put up a tree.
Candles.
Thanksgiving
because it is a traditon
Because they want to.
Some people have a star or an angel on top of their Christmas tree.
Yes, you can. Some people put up their Christmas lights the day after Thanksgiving. Some do wait until closer to Christmas, though (just as most people put up their tree well before Christmas Eve, but some do wait until Christmas Eve).