I don't really like it, but you can make sense out of it if you want to.
The average human power level is probably around 5 (literally the first power level shown in a scouter). Assuming Androids can train their bodies just like average humans, just as Krillin for example, they should be able to power up to AT LEAST 15 000 times their BASE power level (last official known Krillin's power level was 75 000 during the Frieza Saga according to V-Jump, I divided that by 5).
Assuming 17's BASE was about the same as a Super Saiyan Goku (officially 150 000 000 during the Frieza Saga according to Daizenshuu 7), then his power level after training like Krillin did should be AT LEAST 2 250 000 000 000, which is comparable to that of Super Saiyan Vegito (calculated at 2 500 000 000 000*). I do believe someone with that kind of power could provide a nice sparring session for Super Saiyan Blue Goku. Then again, that is only an estimate of his potential, he could be much weaker depending on what kind of training he did, maybe it was more similar to that of Yajirobe's (officially 970 during the Saiyan Invasion according to Daizenshuu 7), which will put him at 29 100 000 000, slightly stronger than Super Saiyan 3 Gotenks (calculated at 28 000 000 000*)
*dragonball.wikia.com
A more problematic issue is where and/or with whom did he train to achieve such a thing? Not to mention why he chooses to fight certain aliens that threaten the Island and ignores others that do not only threatened his conversation efforts but his family as well like Majin Buu.