You could get all of the data from the table and then get the correct indexes as separate Elements:
Elements e = doc.select("td.yfnc_tabledata1");
Element open = e.get(1); // index for open is 1
Element volume = e.get(9); // index for volume is 9
System.out.println("Open: " + open.text());
System.out.println("Volume: " + volume.text());
Will output:
Open: 1,037.16
Volume: 1,613,009
You can't use getElementsByTag("Open")
or getElementsByTag("Volume")
because those tags don't exist.