MY ANSWER IS THIS:
Does seat one call next and if so, what do they lead?
1)
You MUST call Next at MOST any score with 3 trumps. No brainer! Only exception is possibly at 8 to 9 your favor as you have next deal. But even there your chance of scoring is equal to scoring on your deal. What are your opponents are likely to do 9C pass? Anyway to continue.
Justification for Nextn is you have no defense against Diamonds or Hearts - S2. So even with Opponents euchring you it no worse than Passing. And you will stop some loners as well.
2) Do not lead what was turned down UNTIL one lead of trump. So that leaves either leading trump (Spades) or Diamonds.
When you have three trumps, I prefer Trump and would lead QS. You lead 9S it could happen that Dealer is bagging and uses only his 10S if you lead 9S. And trumping 2nd lead of Hearts, the 9S is a good or you can now slough the 9C.
Justification is that IF your Partner is weak it will pull trump from both Defendents. But you need some help with one trick from your partner either a Bower and/or AC/AD/AH. This where you also have Trust a low lead from S4 on trick 2 and slough to get a Void. ALL DEPENDS!
For the Opponents to euchre you they have to have three trumps or Right + AD but your partner can still help here. The left can be buried or with your partner most probable to win a trump lead or force the Right. Chance of bagging is that the Opponents have a strong trump hand and that probability is about 33% and is in your favor. 33% of hearts/diamonds/clubs. A statistical number of the Law of Large Numbers (many hands dealt).
However, that said, It is not Wrong to lead the 9D. Nothing works 100%. And if your partner has all Clubs (probably does) & Spades he can trump. Even if Opponents win the trick you now have options to Slough the 9C or trump. After one lead of trump you can now lead that 10C. Do not worry that one opponent has both JC/JS as that would be a really dumb call to pass from S2.
i would predict calling Next you will score well over 66% of the time either lead. Passing it will be reverse of this.
Hope that helps!
IRISH
“Life is the art of drawing sufficient conclusions from insufficient premises”—Samuel Butler