Translation:The boys hurry there, where many girls walk.
You are putting focus on the place the boys are going to, since you define it in the second clause, so the place has to be in front of the verb, not part of it. If it were odasietnek, the focus would be on the verb instead.
How can we know which is indeed where the focus is? It is not clear to me in the recorded voice where the emphasis is being made.
The emphasis is there, but it might take some listening training to hear it well.
But more importantly, it's part of the oda - ahol construction, so oda has to be a separate word.
Those relative pronouns like ahol, ami, aki, and so on, mostly need a single adverb in the main clause they can refer to.
Why is it ahol and not ahova since there is a movement. Or maybe this implies that the girls are walking on some place like on a square without leaving it.
It implies that the girls are walking in some place without leaving it. :)
Or, maybe better, it's about a place where girls are generally known to be walking. Like a certain street in the city. (Though that does sound a little red-lightish now that I type it out.)