B3 C#4 F#4 G#4 C#5 D#5 E5 G#6 B6 C#7 F#8 G#8
These notes are all diatonic, e.g. from the same key (unlike all the keys on a piano). That key is C# relative minor (or E major). In modal language, this is the C# Aeolian (or, when played from E to E, Ionian mode):
C# D# E F# G# A B C#
If you play notes restricted to a single key, it will come out sounding OK.
Or it could equally well be
G# A# B C# D# E F# G#
(I hear it much more like that too.)
The tonal center we'll hear using this specific collection of notes, whether it be G#, C#, E (or any other note from this key), all depends on the sequence you enter. Rhythmic variation would also support this but this app does not have that option.
Here's one with a tonal center of C#: https://music-grid.surge.sh/#1152-2112-1040-2212-1088-1320-1...
And with G#: https://music-grid.surge.sh/#260-272-528-256-160-288-512-108...
It's unclear to me from your comment whether you realize that.
this scale:
C# D# E F# G# A B C#
is C# Aeolian.
Minus the A natural, that is one collection of notes that is being strongly suggested by this app. Yes, an A# would would change the tonality, and the key.
To me, I hear the 9th scale degree relative to the tonic much more than the 6th (i.e. 13th). That's in general, and it's based on my own predilections and harmonic training. This scale includes a D#, as well as the 4th and 5th. I "hear" this as relative to C#, not G#. Totally welcome, of course, that you hear this as relative to G#; the E natural then functions as the minor 6th. To me, that's a much weaker harmonic suggestion than the E natural functioning as the minor third. It's totally OK with me that we hear this differently. Is it OK with you?
Also, why does it matter to you what I (some random person online) realizes (or not)?