Yes, if you've told us the right notes (clefs and key signatures help a lot!) it's actually A9(b13).
I wonder which came first, the chord symbol or the notes? It's quite likely that seeing 'A7' I'd feel justified in playing that. In some musical contexts, anyway!
Alternatively, it's not unusual for a simplified set of chords to be printed to music that might be played by either a piano or an elementary guitar strummer, who might be scared off by 'A9(b13)'. Let's just hope they don't both try to play it at once, reading their notation literally!