I'm no bash scripting expert but how about something like this (which I'm sure could be greatly improved but will still save you lots of time);
!/bin/bash
NEWMEMBERIP=1.1.1.1
NEWMEMBERNAME=testnode
NEWMEMBERPORT=8080
tmsh create ltm node $NEWMEMBERNAME address $NEWMEMBERIP
tmsh modify ltm pool pool1name members add \{ $NEWMEMBERNAME:$NEWMEMBERPORT \}
tmsh modify ltm pool pool2name members add \{ $NEWMEMBERNAME:$NEWMEMBERPORT \}
tmsh modify ltm pool pool3name members add \{ $NEWMEMBERNAME:$NEWMEMBERPORT \}
tmsh modify ltm pool pool4name members add \{ $NEWMEMBERNAME:$NEWMEMBERPORT \}
tmsh modify ltm pool pool5name members add \{ $NEWMEMBERNAME:$NEWMEMBERPORT \}
tmsh modify ltm pool pool6name members add \{ $NEWMEMBERNAME:$NEWMEMBERPORT \}
tmsh modify ltm pool pool7name members add \{ $NEWMEMBERNAME:$NEWMEMBERPORT \}
tmsh modify ltm pool pool8name members add \{ $NEWMEMBERNAME:$NEWMEMBERPORT \}
tmsh modify ltm pool pool9name members add \{ $NEWMEMBERNAME:$NEWMEMBERPORT \}
exit 0