Without seeing what else was happening it is hard to say.
The lad giving the simul has the advantage that you HAVE TO MOVE the
moment he appears at the board. He is looking to roll over all the weaker
players quickly so he can use his sudden appearance to force blunders amongst
the more experienced players.
I now specualte.
Jessie had marked down RB as a quick win, hence the Morra Gambit.
(he beat RB with Black the night before in 12 moves.)
About now he would have been looking for where his quick wins were coming from.
If he has just faced a series of solid positions and now this then it would have
been a sigh of slight despair.
9...Nd7 is not the best Black move, (9...Nc6 develop) but nor is it an obvious blunder.
No quick win here. He has to dig out a win in a symetrical pawn structure.
So there is some work to do on this board as well. Sigh........
Re the best 3rd move in the Morra. If you are not going to take c3 pawn
then why Not 3...g6.
4.cxd4 d5. 5.exd5 Nf6 Black gets his pawn back. This is playable.