Solunars by Aldebaran Sidereal Academy

Is a planet at around 9°58’ from an angle considered viable as an angular planet?

Natal astrology? Mundane? Progressions or transits? Solars or lunars? Ecliptically or PV?
Is this the only angularity in the whole chart? Is it strongly aspected by luminaries or other angular planets?

It depends on what you are talking about.

In general, I would tend to look at other things first. I'm lazy and if I get a full picture with partile or near partile aspects and strong angularity then I barely glance at the wide stuff.

Yeah, what Jupe said.

These are gradients of relative strength, so it depends on context. No hard cliff-like drop-offs (though the "slope" gets steep in places). If there are other foreground planets much closer, then those have louder voices prevail and the Saturn either supports them or gets lost in the dust.

An example: My only foreground planet is Moon. My second most angular planet, Sun, is solidly middleground; nonetheless, I have to keep reminding myself that, after all, its my second strongest planet. - To the extent that we are deal with the commonalities of two luminaries strong, it somewhat reinforces the lunar characteristics. To the extent that we are dealing with Sun and Moon as polar opposites on certain traits, Moon wins.

Just f'rinstance.