Want to use it more often at heritage sites and the wild life park we only go on holiday twice a year but we just want better pictures.
After quick look those heritage sites seems to be mostly old castles, monuments and such.
I guess you likely want mostly big depth of field images with lots of castle etc in focus, instead of seeing how much of it you can get ouf of focus, right?
That depth of field becomes fast important when watching shots in bigger size.
With HX9V (or camera in your phone) you've never had to consider that, because of always huge depth of field/in focus area.
But with increasing sensor size depth of field becomes smaller for same field of view and f-ratio.
Especially in system cameras you need to learn to take that into account and control camera accordingly.
There's basically "Flat Earth Photography" religion, which forgets to mention that big sensors bring their own challenges.
It's just in other areas than with small sensors.
Heck, in fact for same depth of field every format has same amount of light hitting sensor.
So it's always up to conditions of wanted image in which ways strengths of format/camera work and what you have to fight against.
With tiny sensor you don't want to rise ISO, but on the other hand you can use full aperture even for big depth of field image... While unable to get shallow depth of field.
Again with big sensor you have to always lug around bulk/weight of lenses, whose full aperture you can't use when wanting big depth of field... Forcing use of higher ISO to counter it.
For stationary things like buildings/landscapes starting point/first decided setting is f-ratio, because it controls depth of field.
Then ISO is chosen so that you can keep exposure time short enough to avoid blurring of image from handshake/other camera movement...
Unless you have way to mitigate effect of those, like always available image stabilization, which can give leeway to stay at couple steps lower ISO.
(stabilization and big depth of field of smaller sensor can allow keeping ISO low to lower light level)
For moving targets fast enough shutter speed/short enough exposure time to stop motion is the first factor.
With some minimum considerations for depth of field: Stopping motion doesn't help any if most of target is out of focus.
ISO setting is then basically forced by those to get correct exposure...
Is the rx100 that good, How much better is it than my old cybershot?
I'm not bothered about it being compact but would the canon take better pictures than the rx100.
DSC-HX9V is from time when marketing kept cramming too much marketing pixels to smallest sensors.
That causes lots of noise in anything but best conditions.
Even lowly ISO200 test scene shot shows signs of noise and heavier noise reduction:
https://www.imaging-resource.com/PRODS/HX9V/HX9VhSLI0200.HTM
For example check that colour chart in lower center and those napkins in upper left.
Besides napkins also various bottles/their stickers are good for seeing how much details survives noise and its removal.
With small/low contrast details going to major decline at ISO800
https://www.imaging-resource.com/PRODS/HX9V/HX9VhSLI0800.HTM
Here's same test scene with RX100 at ISO1600
https://www.imaging-resource.com/PRODS/sony-rx100-v/RXC5hSLI01600NR2D.HTM
https://www.imaging-resource.com/PRODS/sony-rx100-v/RXC5hSLI03200NR2D.HTM
Canon 200D at ISO3200/6400
https://www.imaging-resource.com/PRODS/canon-sl2/SL2hSLI03200NR2D.HTM
https://www.imaging-resource.com/PRODS/canon-sl2/SL2hSLI06400NR2D.HTM
And for comparison supposedly bad Four Thirds at ISO3200/6400
https://www.imaging-resource.com/PRODS/olympus-e-m10-iii/EM10M3hSLI03200NR2D.HTM
https://www.imaging-resource.com/PRODS/olympus-e-m10-iii/EM10M3hSLI06400NR2D.HTM
Here you can compare cameras side by side:
https://www.imaging-resource.com/IMCOMP/COMPS01.HTM