Mother/grandmother Drama

I think it makes more sense for your daughter to sit with the rest of the wedding party. Splitting her up from them would make it look as though she is "other than"; plus, she has already indicated she wants to sit with them! It sounds as though your mother is using your daughter's placement for dinner as the means to express her unhappiness with the situation as a whole. I would sit down with your mother and assure her that you understand and sympathize with her disappointment, but robbing your daughter of a once in a lifetime experience that she is really excited about would be selfish and unfair to your daughter. She shouldn't be punished for adult drama that doesn't include her. And forcing her to sit with the family against her will because grandma is being selfish is only going to further damage her relationship with her. Would it be possible for you and your mom to work out a way for your daughter to see her more often moving forward?

Your mother is being quite dramatic about this, and to me that means time for boundaries. I would stand your ground on the seating plan, starting to cave to her wishes may be the edge of a slippery slope.

Sounds like she's feeling unimportant and insecure, so I think tackling that issue might help. I would suggest giving her a special corsage or something to make her feel special on your day.

If it wasn't for the drama and the fact that your daughter is expressing a preference, I would have thought it was a no brainer to seat a 9 year old with her family and extended family that she rarely sees rather than with the older bridesmaids. She'll be spending plenty of time with your future SIL and other bridesmaids between photos, getting ready, rehearsal etc. While your mother may be handling this less than graciously, and while I think she should keep her mouth closed if this Is what you wish, in your place I would have put her with your family.