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Enter the formula below in F26.
=INDEX(Table9,MATCH(F24,Table5,0))
That will give you an immediate result. However, thinking a little into the future, you might anticipate conflict between your dropdown and the formula. Logically, the formula should be over-written whenever the user makes a selection from the dropdown. Then it's gone. Therefore you should probably do away with the validation drop-down and protect the formula instead.
The references to Table5 and Table9 indicate that you didn't name your tables. That isn't good practice. ='Presentation Data'!$U$2:$U$13 to specify the source of email addresses may be idiot-proof in the setup but it isn't that when it coems to maintenance. =INDIRECT("Table5") comes closer but requires the knowledge that the range name must be embedded in an INDIRECT() function here. Idiot-proof maintenance would be assured with =INDIRECT("Emails") but that requires a meaningful name to be given to the table. Of coruse, that same name would also appear in the formula extracting data from the same range.
Note that the formula relies on the sequence of names in tables 5 and 9 being the same. Consider merging the two tables into one with two columns, called, say, Name and Email. In =INDIRECT("Table9") the whole table is specified as a source. While the table only has a single column that is adequate but =INDIRECT("Table9[Email]") would have the same effect, using the column caption to specify it. This addressing syntax would become mandatory if your table has more than one column.