There are other questions here that have dealt with this topic. Basically, there are good reasons why historically certain keys sounded different from others, due to the fact that unequal temperaments were more common, and thus some keys would sound more "in-tune" than others. These aspects of tuning often influenced the choices of genres for writing music in particular keys, so different keys developed associations with emotions or extra-musical characters (e.g., some keys were considered appropriate for "martial" or military type music, often because military instruments were pitched in them, so marches were often written in them).
That last bit is still potentially an issue today: many instruments are still pitched in standard keys, which means they are easier to play (and easier to play in-tune) in some keys than in others. Modern instruments are mostly equipped with various keys and slides and such to help correct for the problems of playing in less-common keys, but there may still be subtle variance in tone, say, for brass instruments playing in a key they are pitched in vs. a key that is a half-step away (which will require much more tuning adjustments, will potentially change the tone slightly by using more valves, etc.). For string instruments, one might consider that sharp keys often take advantage of open strings, which alters the sound. And unless you're talking about truly professional violinist, their ability to play in a key in tune with many flats compared to their ability to play in a key with a few sharps will vary significantly.
So, from a practical standpoint on many instruments, it certainly does "feel different" to play in different keys. Does it therefore also create a different mood? No, not necessarily. But differences in tuning and tone can make a difference, and this was part of the historical origin of the characters of the keys, back when most instruments were quite difficult to play in all possible keys, and various keys would in fact sound quite different due to these practical performance issues.
As for today, the effects are relatively small, and if you're dealing with professional players, asking them to play the same piece in G major or G-flat major or F major isn't going to make much difference. However, if you're dealing with amateur ensembles, there are potential significant differences to asking a group to play in G major vs. G-flat major, and some of those will come out in the sound of various instruments or in the fluidity with which instrumentalists are able to play.
But as for moods and "feelings" associated with specific keys? These were always a bit of a convention, created through associations that built up over decades of composers using certain keys for certain purposes. There's nothing inherent in the sound of different keys that conveys those specific moods.
(The one exception, I suppose, would be for some people with perfect pitch who experience different types of synesthesia. I once knew someone who had a very acute sense of perfect pitch but also had developed very particular associations with keys, including moods, colors, etc.)